Spakle a PU / Clark Blank ??

Aloha … Can I spakle a Clark PU blank before I glass it ? I think the correct way… or 1 way . Is to use lightweight spakle and thin it a little to make it able to apply with a roller and paint brush … ?? I’ll explain why after I find out if it is OK to do it… Let’s say it’s to maybe avoid a mistake that new , less experienced - crummy glassers (like me) do. Thanks for the help… Don

Problem is spackle works great to seal imperfections and voids, but used thicker to compensate for “accidents”, it can cause a spot for delamination because it expands differently than foam, and it’s crush resistance is slightly less.

Used really thin, like about 1/6", should be no problem, but a better solution is adding a layer of poly foam (from sheets availible at your friendly blank store) and just using resin to adhere it. Yes, it will cause a hardspot where the resin is, but much easier to deal with than paper glueup stringers.

Aloha, Thanks Lee DD . Here’s the problem . I hve gotten pinholes on the last board I did . I was told it was most likely in the lam coat that it happened. I am allways afraid that if I don’t hurry the resin will go off before I get the glass laid down . Especally the rails,tucking the laps . So I was thinkins if I was to use Spakle I could lighten up on the catalist and take my time . I am thinking that the spakle will keep the board from soaking up too much resin . Does this make Any sence??? I am not the fastest glasser as I try to take my time somewhat to avoid other screw ups . Any opinion on this idea would be appreciated …

Hotcoat…

Are you glassing with polyester or epoxy. The reason I ask is that if using epoxy, the mixture of resin to hardner is critical, and should not be changed or modified. Different hardner, different pot and working time. You can always do a gel time test. If you are using polyester, then the percentage of MEK-P can be adjusted to extend your pot and working time.

Ken

Thanks Airframe for the reply… I am using poly resin . Not good enough yet to trust myself with Epoxy… I know you can adjust the MEK-P . The thing is I am thinking it might soak up too much resin if it is too slow . Thus the spackle idea?? What do you think ? Iknow… Get someone else to glass it … ha!? … How light can I go on the Cat ?? The temp here in FL is 85 about and the humidity is high as you surely know… Thanks … Don

Don…

Don’t cut yourself short. Resin Research is soooo easy to work with. As for the MEK-P and the poly, you have a pretty good range of percentages to work with. Generally the percent of catalyst should range between .8% to 2% of MEK-P by weight. Resins are tested and designed to perform at a temperature of 77 degrees. Anything above or below that temperature changes the gel and curing times of the resin. This is why you can change the percentage of MEK-P to compensate for the difference in room and resin temperature. With epoxy, the percentages of hardner to resin are not as flexible, and that is why they make different hardners, so gel and cure times can be adjusted in case of various temperatures other than the designed 77 degrees.

It is always a good idea to do a gel time test if your not sure of the amount of catalyst you need to use

I am doing my lay-ups with epoxy in 95 degree weather, and the process can take up to one hour. Try that with poly!

Good Luck!!

Ken

I’ll second Airframe. Try using Resin Research Epoxy with Additive F. I just made my first board in 15 years. The only differences I could find with epoxy were positive ones- it doesn’t smell, it cleans up easier, it gives you more time to work, it goes off gradually. I used their mid range (not slow or fast setting) and had a good 45 minutes before the first signs of gelling occured (at about 78 degrees…Southern California). Another thing I liked about epoxy (with additive F) was that I could sand the lam coat laps as though I had laminated with sanding resin. Then I hand sanded the hotcoat (I was glassing in our condo bedroom!) and it was as easy, if not easier, than poly. No gumming up the paper! Finally, I’ve been using the board now for three months and don’t have even a single pressure ding! !!! I used 6oz/4oz s-glass deck and 4oz s-glass bottom on a Walker foam blank, sealed with spackle. I’ll never do a poly board again. I’d say you’re crazy if you do. There’s absolutely no advantage to poly. Epoxy costs more (I paid $108- including shipping- for 1 and 1/2 gallons) but I did one board using more than the recommended amounts and still have half left over. I’m getting ready to glass my next board. I did swirl tints and everything. First timer. No problems. Check out in the resources section- there is an eps/epoxy construction primer. I did a polyurethane blank. My next step will be to try EPS.

Thanks Everyone , Maybe I will try the resin research epoxy . I know right where his shop is ,as I have bought a few boards from Steve Forstall who is right next door. Guess I will see how the shape comes out to decide if it is good enough to use epoxy. I still wonder thou if I could use the spackle on a poly board (clark) to be able to make a slow gel time batch of lam resin and still have it not soak in to the blank too much ??? Or is is actually the idea to have it soak in and that will help avoid the “Pinhole” problem?? Thanks, Don

Resin soaking into blank while lamination is nothing to worry about.

If it’s gonna set, it sets within an hour, or stays viscous forever.

Whatcha gonna do with 15 minutes work time? You watching TV? Talking on cellphone to your honey? Pickin up pizza?

Just do the work at hand, and 15 minutes is plenty of time.

Gee thanks Lee DD , you allways seem to have a way to get to the point … The thing is that I am thinking that I need the time to work the resin into the weave of the glass more to not have the pinholes? I was told by a few people that the lam coat is the culprit of the pinholes that I had noticed after the hotcoat. You see I rush thru the lam coat to avoid not having the time to lay down the glass on the rails . It looks good but still I had pinholes. I am not as experienced as you so it takes me longer to spread it out on the deck and work it in to the weave then squeegee the excess off . I don’t know . Do you have any helpful words of wisdom for me… Thanks, Don

WHOOOOAAAA there Nelly. Ain’t no reason to spackle - the usual purpose is to seal and EPS or XPS blank so it won’t absorb too much resin, thus drying out the lam. But Clark Foam won’t do that, thus no reason to spackle.

I think your pinholes came from not enough resin in the lam. However, the hot coat should have filled the glass and laid over a nice coat to sand smooth. Think about your laminating and hotcoating processes a bit more. We call it a hot coat because it is intended to go off quickly, so the resin doesn’t drain off the board, and will be nice and thick when it’s time to sand. But really, you don’t have to set it off so it gels in minutes, and it’s probably better not to. As pointed out on this forum, if your lam is a little dry, or somewhat bumpy, a cheater coat of lam resin can be brushed on to provide a little extra “space” for sanding it all smooth.

If you doubt your lam or hot coat skills, there is another way: get, and use, UV cure resin. Practically unlimited working time in an enclosed garage. Take 45 minutes or more to get your lam “just right”. After the trials and tribulations of using catalyzed poly for decades, the freedom afforded by UV cure is fookin great! And it’ll dissolve your anxieties about how fast you’re working. You’ll never mix too much, and dump it on the floor (unless you’re sloppy). Not enough? Just pour some more on (unless tinted/pigmented of course). Best of all, if you connect with someone buying in quantity, it’s A LOT cheaper than epoxy. I pay about $28/gallon by getting 5 gallon cans from Fiberglass Hawaii.

As always, proper PPE (personal protective equipment) is appropriate to poly users. A charcoal cartridge on a well-fitting respirator is a must. Disposable gloves (15 cents a pair cheap enough?) are nice to have. I glass in my slippers, shorts and Tshirt. Cleanup and waste are minimal as I’m a careful glasser and hate to waste resin.

A reasonable glass schedule, derived from experience, has my boards far outlasting shop throwaways.

Some notes: in catalyst days, I used about 0.8 percent catalyst and got a 20-minute pot life. You have to be efficient to get a longboard done in that time. From a book on resin chemistry that Ted Wilson of Fiberglass Hawaii showed me, poly resin is strongest at about a 2% catalyst ratio. Unachievable (too fast) without chilling the resin (which would make it thicker and less workable).

Howzit?!? Air in the glass is one thing, but I think the trick is to use a little extra “elbow grease”, and concentrate on saturating the foam. Just wetting the cloth isn’t going to solve the problem. Get the resin into the foam, and the resin won’t drain underneath, keeping the cloth nice and wet. Most times, the pin airs come from the pits in the blank. For p.e., UV resin is by far the easiest to use. No worries about it going off until you’re ready for it too. Aloha…RH

If you’re not ultra-stressed about a few extra ounces, you can do a light filler coat before your hotcoat and that will also greatly help to eliminate pinholes.

Once your board is laminated, and you’ve knocked down the laps, you simply pour a small amount of laminating resin on the deck/bottom relatively and squeegie with a fair (not excessive) amount of pressure, forcing resin down into the cavities. I then use my 4" brush to carry the filler over the rails and blend it into the opposite side. With UV resin, there are no drip problems as you cure it right after. With a well-time standard cat, it does fine as well, you just keep the brush handy for the potential drips along the rail line until it goes off. You can tape off your tail edge at the same time if you like a really sharp tail.

One thing I like about this type of filler is that it helps you avoid sand throughs on the rails on a sanded finish board, as you have just a bit of extra material to work with in those touchy zones.

15 minutes or 45? It’s your choice. I’d go with RR Epoxy. They even have a slow set. I spackled to avoid the balnk saoking up too much resin which I’d heard Walker foam has a tendency to do and it also fills any imperfections, surform gouges, sanding scratches, and helped make the tints I used more even. Call Greg Loehr. He’s the master and I believe he’s in yuour neighborhood. They have great customer support. He’d call and answer my questions as I went along.

Do not spackle. that is not your problem.

Use UV Cured Polyester resin.

It’s by far the easiest thing for a beginner to work with. You can even buy it pre-mixed thus making it even easier.

Won’t cure unless exposed to UV light, allowing basically unlimited working time.

Less weather sensitive. Deosn;'t really matter the temp, asa long as you have UV light, you’ll get it to cure. Even a cloudy day it will cure.

Only requirements are a working envieonment completely free from UV light. Ie, a garage with windows taped up.

Drew

Aloha, Thanks to all who responded with a lot of good information… I should have known . It was my idea so … Well I am glad I had this forum to go to. I will do one thing at a time shape the board then decide on the material to glass it … who knows maybe I will see this shaper friend and get some Carbon Fiber… ha! … It will take some time to shape this thing anyhow . I am in no hurry it’s a hobby for me. But I just want to say “Thanks” to all of you pros who have given me the good advice… Don J.