Okay, we're gunna do this... [Archive]

woobs

01-26-2015, 04:31 PM

Well, since I have decided to take on my first fiberglass project (1965 Donzi Ski Sporter) I figured that I should start with some planning. Here's the basics of the situation:

An early boat with a tough life. No descript ID at this time. Not a significant boat. The P/O started a restoration... stalled, and now I have picked up the pieces. 90% of any of the original hardware is unusable.

My general plan is to install a SBF 347 stroker (smaller physical size and lightweight) to a modified Alpha One (gen I) drive. I'll be looking at ALL options for everything else. Sort of a "moving target". This will not be a quick project and rather, a marathon. But, you have to start somewhere so here - goes...

Hull:
These early boats have a reputation for a weak factory layup that will not handle modern v8 power. The transom on this boat was cut for an Eaton drive. filled and plated over for an outboard application. Then, restored for a sterndrive application. However, the big round plug is still in the original transom (I don't think it looks too strong). The stringers look strong however, they also seem "cut up". Despite a good outwardly appearance and given their age I think both transom and stringers have earned replacement. The outer hull has been freshly refinished So we'll just ponder that for a while.

Deck:
This deck has been re-cored and is uber-strong. The channels that fit over the gunnels need to be cleaned out of excess glass to facilitate mating/fitting to the hull. The deck surface has been sanded, it is porous and has spider cracks amongst it's many blemishes. did I say it was strong!

Phase one:
Job one - will involve the removal of original fuel tank, transom coring and stringers.
Job two - will be replacement of the transom
Job three - will be the re-enforcement of the hull layup
Job four - will be the replacement of the stringer assembly
Job five - attention to detail items (gunnel chips, etc...)

I would like to be prepared in advance of commencing work so this first Phase can progress smoothly and continuously. And here is where I throw it out for opinions and advice. Specifically on the fiberglass plan. Here's what I need to know:

1) What should the area to be re-enforced cover. Gunnel to Gunnel? Chine to Chine? Stern to beam?

2) Which cloth should I use for this operation (Weight, weave)? Are there options?

3) Depending on the cloth choice options, what should the schedule be?

4) As I am new to fiberglassing... which brand should I use? West System is available locally (Toronto, Canada) are there others I should consider?

Once these questions have been answered and a plan decided then, I will build a materials list & budget. We're on our way :)

gcarter

01-26-2015, 06:22 PM

I've not worked on a 16, but one thing I've noticed is the smaller boats benefited from having approximately the same layup schedule as the larger boats and were stronger for it (or the larger boats suffered from being built a little too light).
Wait awhile before you buy a bunch of hardware, as you may change your mind several times.
Epoxy is a great resin to use, but keep in mind, you (or someone else) can never use ester resins on top of it.
I think vinylester resin is a good compromise and costs somewhere in between polyester and epoxy, and works just like polyester.
Look for regional gel damage (cracks) which may indicate the layup was too light in that area.
Are you looking to import your materials?
I really like 24 oz. Knytex 1708 double diagonal stitchmat for reinforcing. Super strong stuff.

woobs

01-26-2015, 09:03 PM

Thanks George.

Do you think one layer of 24oz Knytex will do it? That's pretty heavy cloth (and will soak up the resin). Do you think Gunnel to gunnel up to the fuel tank is enough area?

I would like to buy material locally. Toronto is a pretty big center... I can't imaging there is many brands we can't get here. The woodyboat guys like West System and I thought it would be a good idea to become familiar with it. Is there a particular brand you recommend? Keeping in mind once I work with it, I'll probably not change.

As for hardware... nothing is set except the Alpha drive (I have one + parts to experiment with). I have started saving what I can from the original stuff and I'd like the old school feel. The SBC is high on the list due to size/weight with the option being the 4.3 V6 (already done one of those)81360813618135881359

gcarter

01-27-2015, 05:40 AM

I would absolutely use epoxy on a wood boat as it's also an excellent adhesive.
But on an old 'glass boat that's built using ester resins, vinylester resin is much
stronger than polyester resin and allows the use of stitchmats w/the layer of
mat attached which aren't compatible w/epoxy.
W/few exceptions, I've only reinforced from chine to chine. You might take a
look at the first 20 pages or so of the TR project where I reinforced the bottom
according to the Donzi schedule. You wouldn't necessarily use as many courses
as I did, but the details of the stringer roots are important.
It's much easier to conceptualize when you think of the bottom "panels" as three
distinctly separate areas of reinforcement, i.e., chine to outside of the stringer
on the port side, stringer to stringer in the middle, and outside of stbd stringer
to stbd chine.
And while you're at it, think of using a 41 gallon tank to replace the 25 gallon tank.
You'll be happy you did.

Morgan's Cloud

01-27-2015, 06:37 AM

As George said , once you go with epoxy you have to stay with it , but after a big resto that's probably not such a big deal later on down the road for any small repairs , etc.

IF you do commit to epoxy , shop around . West has sort of become the household brand name out there but there's loads of other brands now , and cheaper too .

Out in the boonies over here there is very little to choose from but I ended up using Interlux's Epiglas system when I did mine.
When all was said and done I could have bought 1000 gallons of standard resin for what I paid for the epoxy , but there was a BIG saving in price over the West System.

I loved working with the epoxy . It can do so many different things with the additive fillers and there's no guess work with the catalyst mixture. And you can also choose the speed of the catalyst that you want.

gcarter

01-27-2015, 08:21 AM

And while I've used West system, my favorite epoxy is System Three out of Washington state w/dealers in many places.
They used to offer a "How To" book called "The Epoxy Book".....imagine that!
They no longer seem to offer it, so I'm posting it from my files.
System Three offers a much larger, more comprehensive list of products than any other supplier of epoxy resins than I've found.

woobs

01-27-2015, 11:04 AM

Hey, that's a handy guide!
System 3 has a distributor here in Toronto (Noah's Marine). Listed as epoxy resin products. Interlux seems to be about 25% less expensive than West or East systems products.

Who makes the vinylester resins (brand names)?

George, I understand the issue you uncovered with voids under the stringers and the placement of the stringers from the factory. As I am replacing my stringers, my plan is to match the mated surface angle of the stringer to the hull (along the entire length). This should reduce the opportunity for voids and also give a consistent "bedding" for the stringer on the hull.

In looking at your 3 panel plan... I was considering the hull re-enforcement chine to chine before re-installing the stringers. Once the stringers are back in I can adopt the 3 zone plan. Do you think this is a mistake?

gcarter

01-27-2015, 12:02 PM

gcarter

01-27-2015, 12:22 PM

Vinylester: Ashland Aroguard 45
$50.00/gallon.

yeller

01-27-2015, 12:27 PM

I don't even pretend to have a thimble of glassing knowledge compared to others here, but I do know the West System is expensive. I stayed away from epoxy resin when I did work on my boat because:

1) I think it's overkill on our boats
2) It was the most expensive
3) The biggest reason: I didn't want to mix and match resins. Once I used epoxy, then I wouldn't be able to use any other type of resin in that location again. Down the road, if I ever wanted/needed to do more glass work I knew I wouldn't be able to remember what sections had epoxy and what sections didn't.

For what it's worth; when I built my 16C (splash), I did it entirely with poly resin. Poly is considered the lowest grade of resin, but after 18yrs of hard, hard, abuse, structurally the boat was perfect. Didn't even have a single spider crack. IMO the layup is far more important than the type of resin used.

yeller

01-27-2015, 12:36 PM

To give you an idea of what I mean by hard abuse:
I built the boat with a jet drive, so I wouldn't have to worry about ripping a leg off. I boat a lot on a river that is used by logging companies. I lost count of how many logs I hit at high speed. So even though I drove that boat over many, many logs, it held up perfectly.

You're just adding a layer or two of glass to strengthen your boat. I believe you will be more than good with poly resin.

yeller

01-27-2015, 12:43 PM

BTW woobs, I forgot to mention: I look forward to following your progress. :yes:

Morgan's Cloud

01-27-2015, 01:17 PM

Sean, your plan is fine as long as you keep in mind the stringers will be lower than the old ones to keep the same X dimension.
Also, using thickened epoxy to bed the stringers to the hull inside is an excellent use for epoxy.

I made up a paste to fill the strakes with before glassing in the extra layers in the hull bottom .

Those old Donzis don't exactly take any prizes for being heavily built.

gcarter

01-27-2015, 01:43 PM

I was just looking at a "Plastics Handbook" on line that I couldn't copy.
For vinylester resins, the consensus was that VE resin had similar strength of epoxy
but at a much lower cost, plus compatibility w/other ester resins.

woobs

01-27-2015, 02:12 PM

Epoxy seems to be the most readily available. Not hard to find several brands. However, these are the local prices I found today. (Shocked to see West system as the least expensive):

MAS Epoxy... $132.62/gal
West Sys Epoxy... $99.00/gal
East Sys Epoxy... $102.69/gal
Interlux Epoxy... $142.99/gal
System 3...
G2 Epoxy... $102.30/gal
Mirror Epoxy... $150.87/gal
Clear Coat epoxy... $156.01/gal

So, now the hunt for a Canadian distributor for vinylester :)

Scott Pearson

01-27-2015, 03:01 PM

Not a fan of the West System. I'm old school and it must be all Polyester. Mahogany and Co. in New Jersey will ship you everything you might need. Resin, Glass, Balsa, Micro Balloons etc. They are a great company to deal with and supply all the big boat builders.

gcarter

01-27-2015, 03:43 PM

Yeah, we all have our favorite suppliers.
I like Merton's in CT.
They got it all including VE resin for $50.00/gallon.

http://www.mertons.com/index.html

Carl C

01-27-2015, 05:09 PM

Yeah, we all have our favorite suppliers.
I like Merton's in CT.
They got it all including VE resin for $50.00/gallon.

http://www.mertons.com/index.html

Yep. Thanks again, George for your help in guiding me through my glass work. Merton's is the place for sure.

OFFSHORE GINGER

01-27-2015, 05:54 PM

Personally guys I use nothing but Epoxy , and have been for over 40 plus years and to tell you the truth there are some big gains when using Epoxy such as .............a longer pot life which means more work time , less waste , and no stank which is a God send in itself & just curious has anyone ever checked out the prices that us composites has to over on there epoxy ( example #635 - 2 to 1 ratio ) # 1 Gallon of resin with a half Gallon of hardener $ 75.50 which I feel offers a whole lot of bang for the buck . http://www.uscomposites.com/epoxy.html

hardcrab

01-27-2015, 07:30 PM

I use UScomposites too ............. no complaints

woobs

01-27-2015, 10:25 PM

I have spent the evening looking at many suppliers. Unfortunately, if I order product from The United States of America, I must pay the 20% difference in the dollar, shipping, shipping premium (due to hazardous material), duties, taxes and fees. So, a $50/gal of VE resin from CT will be more expensive that a gallon of West System epoxy here.

Otoh, I have found Canadian suppliers like, and get this... Plastics World, located 30 minutes from my house, where I can pick up VE resin for $60/gal CAD. Of course there are other suppliers also, albeit at a greater distance that offer different brands.

For now, I have to do some reading on Vinylester Resin vs. Epoxy Resin and make a decision. I'm not sure $40/gal difference can make that decision for me.

Next we look at cloth.

Carl C

01-28-2015, 06:41 AM

There are so many opinions. I'd listen to George on what to use. All these guys do glass work though so I guess it's up to you what advice to take.

OFFSHORE GINGER

01-28-2015, 07:29 AM

Woobs , one of the biggest advantages of using Epoxy is the pot life considering I often use Epoxies that have a wide range ( pot life ) from 35 minutes , 60 , 75 , 90 , and sometimes higher which means I think you will find your self having to work a whole lot faster just trying to get the resin ( Vinyl / Polyester ) out of the bucket before it kicks which often can amount to a small fortune even though Esters are cheaper with out a doubt they can be a pain , and when it comes to fabric you actually have a wide range to choose from such as S or E Glass or one I often suggest to people is a 1700 Bi- Ax with no chop or continuous strand mat backing .

OFFSHORE GINGER

01-28-2015, 07:55 AM

Quick mention , and that is any fabric like #1708 is really not recommended to be used with any Epoxy resin because these fabrics have a chopped Strand Mat backing or C S M ,which has a binder ( glue ) designed for Polyester resins even though it is sometimes used with Epoxy resins with satisfactory results , the binder - Chop Strand Mat / C S M may cause clouding and prevent thorough wet which most likely means you will be using more resin then need be .

woobs

01-28-2015, 09:08 AM

Thanks for the insight Artie.

Because I'm only a recreational consumer of composites and really only for one project I think it's best to stay with one resin product. Here's my thoughts;

George has said epoxy is good for bonding (stringers to hull). I will assume that this works well for transoms as well. Also works well with wood for possible use on my other boat. Epoxy is much more accessible in the marketplace. It has less fumes and is safer to work with. Epoxy seems more versatile in terms of additives and specialized applications (fileting, bonding, laminating, fairing etc...). It also seems that epoxy is more forgiving in terms of pot life etc.. for the novice. It is by all accounts much stronger and has a good resistance to moisture. While it may be overkill in terms of application, Epoxies seem to be more "user proof" as I don't have to be an expert. The only downsides are the extra cost and being locked into epoxies for any additional work in future. I suppose I can live with that.

So, I have pretty much decided epoxy resin will be the desired product to work with. Now to cloth.

woobs

01-28-2015, 09:23 AM

I have found a couple of options for heavy re-enforcement cloth with epoxy:

1) Bi Axle Cloth +/- 45 Degree. Contains double bias 17oz stitched together at 45 degrees. No mat. $18/yd. (50"wide).

2) Fiberglass Stichmat. Mat & Cloth woven together 0/90 weave. $9.95/yd. (50" Wide)

I imagine I will also need some e-glass so, I'm guessing 6oz, (60" wide) at $9.50/yd. will do the trick along with some 6oz tape of different widths (4" & 6" ?)

Again, here the option is S-cloth 9oz (50" wide) at $18.95/yd. and the above mentioned 6oz tape.

I suppose the potential layup should help determine which product to use. So, can i get away with a single layer of 17oz or Stichmat for just the bottom of the hull? Stringers to be done in 6oz or 9oz s-glass? Lastly, do I cover the 3 zones on a top course of 6oz (or is this un-necessary)?

OFFSHORE GINGER

01-28-2015, 11:17 AM

example http://stores.infinityfrp.com/knitted-biaxial/ 1700 bi ax no mat back $ 7.75 a yard , and even cheaper if you buy the 100 lb roll or 67 yards at one time and to tell you the truth I personally would go with two layers of 17 oz on the bottom of the hull and three for the stringers and the reason being is I am very much old school and still believe that a little more beef structurally never hurts................. considering I have an old habit that I picked up while working at another Boat Co which is something I still do this day and that is ...............................I always go with three layer layers of fabric on Stringers , etc , which might be over kill to some but if you decide to just go with two layers of fabric ( 17 oz ) on the stringer's you should be just fine .

gcarter

01-28-2015, 12:32 PM

IMHO, 0*-90* cloth is a NO-NO! It was one of the reasons Donzi Classics were weak. Every place the cockpit ripped apart was due to insufficient material in the axis of stress. 45* will almost always give additional strength.

woobs

01-28-2015, 02:34 PM

What about a course of 45*, covered by another of 90* or vice vera?

gcarter

01-28-2015, 03:42 PM

Sean, think about where the stress is and what's happening.
If the hull is bending fore and aft due to waves, etc, running a course across the hull (perpendicular to the longitudinal axis) won't add a bit of strength.
Diagonal adds strength in both axis.

woobs

01-28-2015, 04:14 PM

OFFSHORE GINGER

01-28-2015, 05:56 PM

woobs

01-28-2015, 06:52 PM

Sean ..........................................to tell you the truth if you are going with a vinyl or Polyester resin your best bet or all around fabric will be #1708 which will....... and foot the bill for any phase of your project , and not to be rude but why ......do I I feel like you are playing me ............................hmmmmmmmmmmm ?

Pretty much decided on Epoxy from all I have gathered in the past few days. If I did use VE I would use 1708 because George said so... and I have seen the successful results of a similar project in his thread.

Playing you? I don't have any idea of what you are accusing me of. But, feel free to comment, or not. I asked for advice, suggestions and participation only (kinda what these boards, and this community is about). I'm a big boy and will make my own decisions based on the posts from here and what I learn through my own research in relation to my project goals. I do appreciate all that participate and all positive comments are welcome. But, if you don't want to play, feel free to spectate. :)

I do ask a lot of "dumb" questions. But, I am very new to this and down the road others will be able to follow this thread and not look as stupid as I do ('cause they will have the answers to the "dumb" questions without asking). Also, I think about this stuff quite a bit and may out smart myself from time to time, which again leads me to look quite thick. The silver lining here is the great quality and character of people in this community and on these boards. BTW, Thanks.

gcarter

01-28-2015, 07:20 PM

I understand the 45*+/- , just trying to cover all the bases :)

It could just be more ignorance on my part but, here's how I thought those two patterns would run together, giving support in 4 directions.

81368

Also, I was thinking the "spray line" or "pressure line" down the hull is not totally perpendicular to the midline of the hull and I figured the more directions of support the better.

81369
If I'm wrong, and I probably am; is there another glass weave I could supplement the 45* with that would give support in more directions? Or, do I even need to worry about the spray/pressure line?

Sean, you're not building a hull from scratch, you're reinforcing your 16! :)
Your 16 hull is built from 0*-90* stitchmat and heavy roving......all laid in the same axis.
It already has all the longitudinal and transverse reinforcement it needs.
You are reinforcing the hull by, hopefully, using double diagonal stitchmat w/the roll laid longitudinally.
I probably wouldn't use more than one course unless you see a lot of spider cracks in an area.
The exception would be the stringers, which you're starting from scratch. I'd follow what I did on the TR
which thouroughly integrates the stringer root into the hull.

OFFSHORE GINGER

01-28-2015, 07:22 PM

Sean , it is all good , and I wish you great success with your project ................Take care and God bless .........................Artie

woobs

01-28-2015, 10:19 PM

...You are reinforcing the hull by, hopefully, using double diagonal stitchmat w/the roll laid longitudinally. I probably wouldn't use more than one course unless you see a lot of spider cracks in an area. The exception would be the stringers, which you're starting from scratch. I'd follow what I did on the TR which thouroughly integrates the stringer root into the hull.

Yes, probably guilty of over-thinking...:boggled:

That does sound like the right thing to do. So, that's exactly what I will do! I guess that puts me back in the market for VE resin & epoxy. :)

Thanks for walking me through this. I had no idea of what the factory layup was on the early 16 or, even where they fail (just that the early ones do). We'll find the actual cracks when the snow is gone :bonk:. In any case we now have a plan and the next step will be to measure, figure, and make a materials list.

Morgan's Cloud

01-29-2015, 06:36 AM

We'll find the actual cracks when the snow is gone :bonk:.

A few years back I looked at a 16 that was the same vintage as yours over here. It had been previously re-painted .. the entire hull .
Just as my St T had , it had cracks visible on the full length strakes about 3' forward of the transom . I'd guess that this is a definite Donzi weak spot in the older hulls .

woobs

01-29-2015, 11:56 AM

That's good info! Thanks.

This boat has definitely had a tough life although, I don't think it has veer been "overpowered". If I were to guess I'd say the Eaton/Ford that was factory probably became too much of a burden (reliability/maintenance wise). At which point this boat probably sat until it was adorned with the O/B. Just by the fact it had survived with it's original layup is probably is the biggest clue.

81374

It has been recorded that the early 16's light layup was NOT conducive to a modern repower with big HP/torque which caused the hull to fail. I don't know which actual area failed or, how this came to be. My hull has been repainted on the exterior so I cannot see any clues there.

81375

I DO know that re-enforcement is required and we will hopefully (or not) see more when the stringers are pulled out. In any case it's difficult to make a plan when you don't know exactly what you are guarding against. Cracks along the strakes will be high on the priority of places to check. I do think we have the beginnings of a good general defensive plan. As has been suggested, I also think filling the strake voids internally with epoxy putty is a good addition to that plan.

yeller

01-29-2015, 12:16 PM

Morgan's Cloud

01-29-2015, 12:37 PM

If you're using epoxy primarily due to the pot life, keep in mind that pot life is proportional to the amount of hardener you add. You can increase or decrease the pot life of any resin by adjusting the amount of hardener added.

IMO I'd steer clear from epoxy when your boat is built with polyester. I always think waaayyy down the road. What about the next guy that has the boat and wants to do some glass work. He's going to be screwed when he tries to use another resin...because he doesn't realize the boat has both poly and epoxy. If you want a better resin, then use vinylester.

But........all these guys have better glass experience than me. I just thought I'd throw it out there to try and confuse you. Isn't that what forums are for?? :boggled: :biggrin.:

I do know that to a slight degree this is true with regular fiberglass resins , but only within certain increments.. A small amount under and it will harden slower , too little and it won't go up at all . At the other end a weenie bit more and it'll go faster , but too much and it won't go off either .

With epoxies you have the option of using slow, medium or fast catalysts ,and it's all done on the same predetermined ratio .

I found that due to the high ambient temps out here I switch from the standard hardener to the slow and it was great.

But remember to use a plastic or wax paper tub for mixing as it transfers the ambient temperature much much slower than a metal one.
If it's too warm and you have a large enough batch once that thing starts to heat up it's too late !

woobs

01-29-2015, 12:37 PM

Lol. Yes, I took my beating a few posts ago :). If I want to use the double diagonal 1708 Stichmat (and I do). I must use polyester or vinylester resin. However, I will still need epoxy for bedding stringers and the laminating the transom pieces. Oh, whoever said this would be uncomplicated... nobody. Nobody said that ever. :)

So, the current phase one plan, order of operations after cleaning out the old transom wood and stringers is:
1) Replace transom
2) fill strakes
3) Replace stringer assemblies
4) Re-enforce hull bottom (with 3 zone strategy to integrate stringer root)
5) Repair other areas as required

OFFSHORE GINGER

01-29-2015, 12:40 PM

If you're using epoxy primarily due to the pot life, keep in mind that pot life is proportional to the amount of hardener you add. You can increase or decrease the pot life of any resin by adjusting the amount of hardener added.

:boggled: :biggrin.:Sean , not to stir the pot but if you decrease the amount of hardener when using Epoxy other then what is suggested by the manufacture you will be wasting your time and money which is why most Co's make a wide variety of hardener's from very slow or tropical blend , to slow , med , and fast .

hardcrab

01-29-2015, 12:45 PM

Artie's got it right - adjust pot life with type of catalyst, not quantity

gcarter

01-29-2015, 12:53 PM

I have a multi-page temperature dosing chart for gel.....I'm thinking it's similar enough it might be useful.
Add a syringe for the mek, and you should be ahead of the game.
I scanned it some time back. I could post it if you or anyone else wants it.

Carl C

01-29-2015, 01:03 PM

Got the full steering on that thing yet? lol I was just re-reading my thread from my repower and glass work. Wow. I will never post another project on here!:nilly:

woobs

01-30-2015, 07:14 AM

I'm pretty much a "follow the instructions" kind of guy. Especially with my lack of experience with fiberglass I would not dare to think I could know more than those that manufacture and work with the stuff. I'll probably use "slow" catalyst and mix as directed.

So, is there a formula or chart somewhere that helps estimate the coverage of resins with different cloth options?

George, is it okay to bed stringers and laminate the transom with VE?

gcarter

01-30-2015, 10:07 AM

George, is it okay to bed stringers and laminate the transom with VE?

In the old days, bonding was done w/resorcinol adhesives. About the mid '50's though, there's nothing better than epoxy.
I believe in using the best product for the particular job.
In "The Epoxy Book", the advantages and disadvantages of epoxy used in boat building are outlined.
For instance, If an epoxy/glass composite boat is built, it must be kept painted because epoxy will badly degrade in UV radiation.
Not so much w/ester/glass composites. Also, there is no "gelcote" alternative for epoxy, so paint must be used.
Unless a "two-stage" epoxy is used, epoxy will weaken in warm water and high ambient temperatures.
OTOH, epoxy is strong, and dosing is easy.
I've already outlined my reasons for staying w/ester resins on old glass boats. My solution for strength is to use VE resin which has
essentially the same strength as epoxy, complete compatibility the existing materials, and a good resistance to moisture osmosis.
Oh yeah, it's also cheaper, and stitchmats can be used.
So, I use thickened epoxy to bond stringers, transverse frames, etc, but notice I don't let the epoxy protrude outside of the covered area so ester resin can be used on top of it. Laminating is also done w/epoxy.

yeller

01-30-2015, 11:31 AM

I do know that to a slight degree this is true with regular fiberglass resins , but only within certain increments.. A small amount under and it will harden slower , too little and it won't go up at all . At the other end a weenie bit more and it'll go faster , but too much and it won't go off either .

With epoxies you have the option of using slow, medium or fast catalysts ,and it's all done on the same predetermined ratio .

I did not know that. Good thing I put in my disclaimer and referred to you guys. :biggrin.:

I don't have the chart, but I thought I remember there being a working range of about 15min to 1h.
Thinking more about it...some of that extra time may have been due to the ambient temps and I was able to get more working time, being up north.