epoxy and FG questions for redneck truck camper

[MudFlap]

as always, thanks for the great info.

Sounds like wet sanding is the way to go. A question on that:

At this point, I have a seal coat on the roof of the camper, but walls are still bare plywood. I would not want to get those bare side walls wet. Of course, I could (and might) go ahead and do a seal coat on all walls also to (somewhat) protect the plywood from excess water.

*BUT*, I have the camper in the corner of a shop, and the slab does not drain the way that I would want to, so I'm not too keen on dragging in a garden hose to rinse after sanding. At this point, camper would be very difficult to move.

I've read that some use minimal water. Maybe a small bucket or perhaps even a spray bottle. Apply water to sanding block or surface to be wet sanded, sand away for a bit, wipe up with paper towels, another squirt and wipe for a final rinse and move to next spot.

Is that sufficient?

Oh yes, almost forgot: you mentioned that before wet sanding, you washed with warm water and detergent. In my shop, I use (diluted) Dawn dish soap and/or Simple Green for general cleaning. Either/or of these be OK?

[tony.latham]

I'm the guy that used the word, Neandrathal for hand sanding with Tom. A (dry) random orbital sander works fine on cured epoxy. (As with all dust, you need to protect your lungs.) And just because it's hard, doesn't mean it's fully cured. Give it two or three days.

But pick your method and have at it. Both will work.

Glass/epoxy needs to be sanded to take the shine off for painting or varnishing ––and that's it. You don't need to (nor should you) sand into the glass. A tiny bit is fine. Thus the dust shouldn't be a big deal on your skin. I never got "the itch" with my last build.



You'll find out soon enough that fiberglassing isn't a big deal. Just make sure --as others have said-- to mix small batches of epoxy.





Tony

[Tom&Shelly]

I've read that some use minimal water. Maybe a small bucket or perhaps even a spray bottle. Apply water to sanding block or surface to be wet sanded, sand away for a bit, wipe up with paper towels, another squirt and wipe for a final rinse and move to next spot.

Is that sufficient?

I agree with everything Tony said. But I was always afraid that with a power sander I'd go too far and hit the epoxy. Didn't actually try it, so it's probably not a problem.

Won't say this is the best way to wet sand, but it worked for me so I stuck with it: I used an old mixing bowl with maybe a pint to a quart of water, changing frequently. 120 to 220 grit wet-or-dry sandpaper. I did a relatively small area at a time, certainly no further than I could reach comfortably. I did not use a block--just sanded with my fingers; rotating motion. Mostly I only took the shine off, but I also sanded out any drips, runs, or other high spots in the fully cured epoxy. I used old towels to dry and wipe off epoxy dust.

I probably spent three or four evenings on each side (horizontally). It's certainly more time consuming, but it was invigorating for a few hours at a time in the fall or winter in a cold shop. Then, I'd come up to the warm cabin, grill some meat on the fire, and relax



Fire hot; food good!

So what's wrong with being a neanderthal?

Tom

[tony.latham]

So what's wrong with being a neanderthal?

Well... one could argue that since they walked this earth about 200,000 years longer than we have... nothing. Except their tools were a bit on the low-tech side. (Did you try scraping the fiberglass with a rock?)



But they camped in caves... Humans camp in teardrops.



Tony

[Tom&Shelly]

their tools were a bit on the low-tech side. (Did you try scraping the fiberglass with a rock?)



But they camped in caves... Humans camp in teardrops.



Tony

Someone found my old toolbox!

You just can't buy tools like those anymore.

Tom

[wysedav]

I'd recommend going to Nick Schade's website. He build strip kayaks and goes through all of the details on how to fiberglass. It's really easy, you probably didn't need a seal coat unless your going clear,sometimes it sucks the epoxy out of the fiberglass and leaves it a little white which isn't ideal if you're going clear. Put your fill coats on before you start sanding, wait a week or so before sanding so the epoxy is nice and hard, hit is with 60 grit and then 80. Paint away. If you get runs in the epoxy (which you shouldn't if you squeegee well) it's easiest to use a razor blade as a scraper while the epoxy is still green. i built a few boats and once you get the rhythm, it's pretty easy.

Good luck.

[MudFlap]

Thanks for all of the e-hand-holding.

I'm cranking right along now.

Did an all-over "seal coat", let cure, then a light wet-sand (using spray bottle, sanding block and paper towels).

Then picked a side and laid in the fiberglass, followed by three fill coats, all about 8hrs apart. Tedious, but not too difficult.

The only thing that didn't go quite as expected is I picked up a healthy "orange peel" texture with the fill coats.

As this was a vertical side, I had to apply the epoxy with a roller, and I erred on the side keeping the roller fairly dry, so very little squeegeeing was required. In some areas I did a little squeegeeing, others hardly at all, and the results were still the same. On the last coat, I tried a little "tipping" with foam brush. Looked better for a few seconds and then ... back came the texture. Maybe should have done that on previous coats?

Not a big deal. I'll knock down the high spots a little when I sand before prime & paint, and I don't really mind a little texture. Just a bit surprised that the texture got rougher with each fill coat layer.

Is that normal? Does it mean that my fiberglass will fly off when I least expect it? haha

[tony.latham]

Is that normal? Does it mean that my fiberglass will fly off when I least expect it?

As my propane installer friend once said, "it shouldn't blow up."

Were you using rollers specific for glassing?

Me? I'm a steeley-eyed squeegee guy.



Tony

[Tom&Shelly]

The only thing that didn't go quite as expected is I picked up a healthy "orange peel" texture with the fill coats. ... Is that normal? Does it mean that my fiberglass will fly off when I least expect it? haha

I'll answer your second question when we finally have ours out and running!

Shelly and I were surprised at the surface appearance on ours as well, the first time we did it. Came right out with mild wet sanding though. Shelly does often tip off for me with a foam brush after I roll (with white rollers), and it makes it look a little better pre-sanding. Not convinced it's necessary though.

Yours is probably fine.

Tony, one of these days, I'll try a project your way, to see what the difference is. (I'll have to buy a circular sander first.)

Tom

[MudFlap]

Learning as we go.

The rollers I used were "high density foam" (bought from Raka). No nap, fuzz, etc. Since I'm working on vertical walls, I *think* that I have no choice but to roll on the epoxy. I'll tackle the roof last and will forego the roller there. Looking forward tackling that last surface.

Brought Mama out to look it over. She's used epoxy to make tiny little nick-nack stuff and she immediately said:
1. The texture is from very small bubbles in the epoxy and
2. You can get rid of them by applying a little heat with a heat gun while epoxy is still wet.

So add "heat gun to fresh epoxy" as another thing I've never done before, but will give it a try!

note to self: make sure insurance is up to date before taking heat gun to epoxy. =)

In the end, if there's a little texture left after priming and painting (semi-gloss white), I'm fine with that.

[MudFlap]

Did a little Google'ing after I posted the last note, and sure enough, heat seems to be the key.

Found a couple good videos:

https://www.youtube.com/watch?v=yragutQn-fM

and

https://www.youtube.com/watch?v=-CVzcAF-wTU

On the first video, she also uses a toothpick to move the bubbles to the surface one by one. If the sides of my camper were 4 square inches instead of 100 square feet, I might give it a try, but since not, I'll try the heat gun.

Sure enough, the second video clearly shows the bubbles disappearing pretty quickly!

[tony.latham]

Since I'm working on vertical walls, I *think* that I have no choice but to roll on the epoxy.

I get the vertical issue. For the front of my "roof" I applied it with a brush and then ran the squeegee over it. If I had had a Raka brush, I'm sure I would have used it.


Tony

[MudFlap]

Thanks for your help Tony.

One stressful part of this process is that once you pour the hardener into the epoxy, clocks start running.

On the first video I posted above, I was surprised that the girl mixed up a batch of epoxy, let it sit around for a while, then leisurely broke out the heat gun and zapped the bubbles in the mix cup. Heck, once I'm done mixing the epoxy, I'm practically running to the camper to get the epoxy applied ASAP. Of course, all the girl needed to do with her epoxy is pour it into a mold. How long does THAT take!

But as you've said, we're not launching rockets here, and it does appear that the process is a little more forgiving than one might expect...

[OP827]

Thanks for your help Tony.

One stressful part of this process is that once you pour the hardener into the epoxy, clocks start running.

On the first video I posted above, I was surprised that the girl mixed up a batch of epoxy, let it sit around for a while, then leisurely broke out the heat gun and zapped the bubbles in the mix cup. Heck, once I'm done mixing the epoxy, I'm practically running to the camper to get the epoxy applied ASAP. Of course, all the girl needed to do with her epoxy is pour it into a mold. How long does THAT take!

But as you've said, we're not launching rockets here, and it does appear that the process is a little more forgiving than one might expect...

I have to mention that it is possible to mix a large amount of epoxy and stir it for one minute and it will not go off unless you have poured it onto a surface for lamination within 2 or so minutes. Once it is on the laminating surface it will never go off since the heat is being dissipated. Later in the build I mixed about a quart of epoxy at a time and laminated large surfaces that way. The girl in the video could be using other type of epoxy designed for pouring (like table tops type) which has longer working time than traditional lamination 5:1 mix ratio epoxies that would go off faster. Lately I used newer 2:1 mix ratio generic epoxy that had at least twice curing time of traditional 5:1 epoxies. And then there are various speed hardeners... so it depends on a variety of factors.

[tony.latham]

I was surprised that the girl mixed up a batch of epoxy...

I don't know what kind of epoxy she is using but I think I could get in a lotta trouble even with Raka's slow-set hardner.



Tony