Fiberglassing without a bag 101

[Shiyuchi]

Lowes or Home Depot. I paid 15$ for a tub of resin and 6$ for fiberglass cloth. I haven't tried it yet but I heard you can lay wax paper or parchment paper on top to get a smoother surface. I also recommend buying a 97 cent plastic putty knife instead of a credit card, if you're doing a large surface.

That's really cheap resin, have you used it yet?

[yamaslobber]

i was wondering if anyone had any tips for applying epoxy on a board with lots of concave and a kicktail, because i recently did this and on the top some of the epoxy kinda puddled in the middle, and on the bottom some dripped off the sides.

the only thing i could think of was maybe letting the epoxy sit for a little while before applying so that it wouldnt run as much. or after waiting a bit heat it up so that its thin and goes on evenly but wont run since it will soon go back to room temerature.

Here is my two cents. There is a huge mix of opinions going on in this thread, a lot of which are extremely off topic. But I saw your question, and I think it applies well to the thread and represents a lot of the frustrations of those initial glassing runs.

Two things. One, you are correct in your thinking that letting the epoxy kick for a while will thicken the mix, and in theory allow you to have less pooling. In all my experience however, it really does not help to let the epoxy sit. And here is why: The opoxy will have a certain amount of surface tension that wants to pull it back together. The resin that has soaked in to the fibers cannot get pulled back because it is in a good suspension in the fibers. Any resin thats floating over (on top of) the fibers however will tend to pool. Getting a thicker mix by letting it sit in the pot will not help this. In fact you have to sit and wait for longer to even see the pooling taking place. By the time you realize whats going on you have high spots and you have already walked away, making for more (and difficult) sanding later on.

The solution is simple. You want a thinner resin. We use an additive called Additive F which gets added to the hardener to thin out the mix even further. But it is not absolutely necessary. Additive F is a whole other post, not something to get in a debate about here. But research it for yourself, or better yet, try it.

Ok, so back to your question. You just need to make sure you are using a nice flexible plastic spreader, preferably one made for glassing. After you let the epoxy soak into the glass, and you have a nice saturated even looking soak-in, keep an eye out for pooling. There is no need to push too hard with your plastic spreader with epoxy. I repeat. Do not "push" epoxy into the cloth. Give it time to soak in, and watch for pooling. Where the pooling is happening, just make nice smooth strokes with your plastic spreader until you get all that excess resin moved off the board. By that I mean dripping off the sides. Wait a few minutes after this, because in the extreme concave areas, you will still get some intense pooling. Smoothly, spread off the excess resin. Additive F will help this happen much easier.

Oh, and as far as resin dripping under the board, just use a strip of tape all the way around the edge of the board. this keeps the everything dripping straight down.

Remember that one of the main things beginners do is leave too much resin on the board when they lay the glass down. You should be able to see even fiber texture on the whole board when you use side light. (doing it in overhead light is a huge handicap)


Oh and NEVER EVER EVER heat your resin. Well, ok, sometimes pro glassers heat there resins to get them the optimum 85 degree temp on a cold day, but they are professionals. My advice is to wait till you have a nice outside temp, between 75 and 90 degrees.

[Pat S]

Will wax paper stick to epoxy resin?

[geolemon]

Will wax paper stick to epoxy resin?

Most likely the wax will form a pretty good release agent... that's just a guess though.

For more curved shapes, tin foil sprayed with a thin layer of WD-40 makes a good mold release as well... and if you miss with the WD-40 at any spots, the tin foil tears neatly and is easy to sand off.

Either way, it's always smart to mix up a little dollop sized batch, take a snippet of matting (or cloth), saturate it, and give it a try - stick it to the wax paper and see if it cures. Or the WD-40 on tin foil.

[geolemon]

That's really cheap resin, have you used it yet?

Home Depot resin can't be trusted!
Seriously though...
Home Depot is notorious for letting things sit past expiration, and expiration dates aren't clearly marked on most containers of resin. You have to find codes, and just about call the manufacturer up to interpret them, as well as find the shelf life for the specific product.

I had some Elmer's brand resin that I picked up from there (I didn't know Elmer's made resin!) to do a little work on some fabrication in my car - I was just bonding shaping fleece to MDF, so polyester resin was OK.

I opened it up and poured it out into a mixing cup, and it had that signature booger-green/brown tint of resin that's turning bad.
I gave it a shot and used it, and it worked OK for what I was doing (which was certainly NOT any sort of critical application!), but it was definitely compromised. At the other Home Depot near me, I checked their inventory of resin, and I couldn't find a date code anywhere on this Elmer's stuff - but what I did see was a really significant layer of dust on the lids! If nothing else, that indicates that Home Depot just doesn't turn their inventory of resin over much... and it makes sense. When you think of "fiberglassing", do you think of "Home Depot?" Not unless you live in a houseboat...

I had the same issue with a can of contact adhesive - Wilsonart brand - I thought I was getting the premium stuff, it was for applying a laminate (like Formica), and this was in fact segmented off with the laminate specialty tools, and carried a little bit of a premium price tag over the standard gallons in the paint aisle. That was awful - it never developed tack. That had clear date codes on it (well - you still had to interpret them via the technical data sheets on the Wilsonart website ) I went back to return my expired adhesive (which they did, despite my opening it), but couldn't exchange it, because EVERY can they had in stock was expired! And they had probably 12 gallon containers left. I told Customer Service... that was at least a year ago, and last I looked (granted it was months ago) they still had the old stock out, for sale.

So... with polyester resin, be careful you don't get green stuff!

[backwoodsboarder]

when sanding before you put your resin down what grit do you want to use? everything i have seen they talk about how epoxy sticks better to ruff surfaces but how ruff?

[geolemon]

when sanding before you put your resin down what grit do you want to use? everything i have seen they talk about how epoxy sticks better to ruff surfaces but how ruff?

It's not just epoxy - in fact, polyester resin doesn't stick to shiny/smooth surfaces at all.

Use as rough of a sandpaper as you can.
I've always got 40 grit around here, sheets and adhesive-backed sheets as it's always my starting point for shaping up MDF and cured 'glass.
Once upon a time I got my hands on some 20 grit stuff that was on a cloth backing - almost like an emory cloth. That was some nice stuff, that's all I used it for actually was roughing things up! I only had one sheet - got it from a friend in construction or something odd like that.

But at any rate, the good news is that wood is porous, fundamentally. If I were going to ruff it up, I think I'd use a very course sandpaper and sand only with the grain - open up the grain without breaking it. For finished hardwoods, this might even be needed to "unfinish" it... but at least epoxy is fundamentally adhesive - even to hard surfaces. You definitely can't say that about polyester resin.

[Shiyuchi]

I've used 60 grit on the four boards I've made, and I've had no problem with any kind of de-lam.

[wallstreetjazz]

Mylar is the best stuff to get a smooth surface you can find it in Longboard sized sheets online. It's clear too so you can work out any air bubbles. If you don't want to spend the money for mylar (literally $3.00 for a 24" by 48" Sheet, you can cut it in half and have 2), you can use wax paper, a thick garbage bag, aluminum foil anything that's flat really. Spend $3 for a tub of vegetable shortening, and rub a thin layer on what ever you use, epoxy/resin won't stick at all.

[Baer]

k...
im a noob at this glass ####.

but i built a board and painted it up all beautiful. then decided i wanted to fiberglass it. i bought resin thinking i would just throw it on and be done, but apparently there is some fabric stuff? im totally working with negative five experience at this fiberglass ####. but what is this cloth? is it see through so i can see my paint job? how do i put it on? and if i put it one should i do the insides of the drilled out holes for the truck bolts?

[geolemon]

Fiberglass is a structural product. Boats are made of it.
It's layed up sort of how you'd do paper mache... paper mache without newspaper would be like a puddle of paste water, right?

You have a woven cloth (or chopmat), and basically the fiberglass resin performs the same role as the paste water in paper mache - it binds your pieces of cloth or chopmat together.

Or, in our case with skateboards, it bonds the cloth/chopmat to the board.

If you didn't use any, don't sweat it too bad - at least you've got a mean clearcoat on your board now!

[jasonbolt]

Sorry if this had been answered before but i didn't want to go through all 5 pages :P but if you could post a link of what fiberglass to buy, what thickness, and what resin to buy, that would be extremely helpful.

[silospen]

Sorry if this had been answered before but i didn't want to go through all 5 pages :P but if you could post a link of what fiberglass to buy, what thickness, and what resin to buy, that would be extremely helpful.

Well, the type of fiberglass depends on what you're using it for (weight, stiffness, torsional strength etc), the "thickness" would be the weight (which again depends on what the use is) and the type of resin pros and cons are outlined in the first post of the thread.

[EMOisFLAT]

Wow, nice work. I'm impressed. My old dervish is cracked and i ripped the nose open the other day and epoxied that shut. Im getting a new one for a discount so i might just try this on the dervish. I should probably try it on a deck i dont care about first.

[aznmobsta]

i am very confused! what thickness birch do i need 1/4" or 1/8"!??!? do i press the wood normally with wood glue then fiberglass? or use fiberglass with epoxy instead of woodglue? so it would go:

1/8birch
fiberglass
1/8birch
fiberglass
1/8birch

also what would be the best type of fiberglass and epoxy to get if i wanted to make a flexy board? and how much does that normally cost?

sorry for sounding like such a noob but i really want to start fiberglassing!

thanks

[hoch92000]

i am very confused! what thickness birch do i need 1/4" or 1/8"!??!? do i press the wood normally with wood glue then fiberglass? or use fiberglass with epoxy instead of woodglue? so it would go:

1/8birch
fiberglass
1/8birch
fiberglass
1/8birch

also what would be the best type of fiberglass and epoxy to get if i wanted to make a flexy board? and how much does that normally cost?

sorry for sounding like such a noob but i really want to start fiberglassing!

thanks

These are all just the right questions every board builder has asked. Funny how the same questions come up time after time.

Searching of course would help.

Even better (and probably your eventual path if you plan to build a few) is to simply try different things. Everything you've asked is a feasable option.

The easiest way to break into composites, is to take a flat 3/8" or 1/2" BB deck, then glass the bottom. Keep glassing until the desired flex is achieved. Factors to consider are your weight and the wheel base. I'll let you figure that out.

Next try, glue (use wood glue or epoxy) 3 or four pieces of 1/8" BB into flat concave (Brodie press) or 2 pieces of 1/4" BB into flat camber (toothless method). Then again glass the bottom untill your desired flex is achieved. Factors now are again your weight, wheelbase, but also consider the camber or concave (not to mention number of glue layers).

Forget about glassing between layers.

After you are bored with this, your next step would be to manage a composites/core system in a vac bag.

Good luck. Try different things, and remember to give back to the fish, the knowledge which you have gained.

[hoch92000]

Oh, use any two part marine expoxy (usually from a boat store) and start with 6 ounce cloth.

[phil6x]

SUCH A GOOD POST!
a few q's though
1.) is it possible for me to do a layer on top, and a layer on bottom (e.g. grip side and graphic side?)
2.) Could i just stick a graphic on to the wet fiberglass, then put another layer of glass on top of it?
(so the graphic would be sealed between to layers of glass?)
3.) prices to cover a mini? say 2 layers per side, so 4 in all? 32 inches long, about 9 wide?

[geolemon]

Forget about glassing between layers.

Why?
If you are using epoxy to laminate it up anyway (and why not - that would simplify the assembly), if you put a layer of cloth between plies as well, you'll increase the rigidity of the board more than just the wood-on-wood bond, and/or get the desired stiffness with fewer plies of wood. Not a bad thing.

[hoch92000]

Why?
If you are using epoxy to laminate it up anyway (and why not - that would simplify the assembly), if you put a layer of cloth between plies as well, you'll increase the rigidity of the board more than just the wood-on-wood bond, and/or get the desired stiffness with fewer plies of wood. Not a bad thing.

Yes, you certainly would. However, that same glass on the bottom of the board would do more to stiffen the deck. Between plies, it would increased the strength of the wood around it. If it is placed on the bottom, it resists flexing of the board by fighting stretching more than a middle-of-the-core placement. Glass on top helps by fighting compression. Totally glassed core = really stiff.