Well, I finally got around to making a nice little LDP deck. It gave me an excuse to get back into doing some composite work. This time I went for 3 1/8" BB plys, stiffened with glass to get the right flex, for my 200 some odd #'s. The design was of course inspired by Roe, Subsonic, LBL, and of course Samhell with Galac. Thank you all very much. I have been educating myself in the art of LDP and deck construction. It is about 9" wide with 27.5, 28.5, and 29.5 WB selections.
One needs a deck with some snap with reasonable stiffness. BB with enough plys can be stiff and function excellently for LDP, but has no where near the snap that glass/carbon can give, for a slightly flexy board. It's got some, but compared to glass/wood deck, it feels gushy and dampening.
The press and stain came out great. The graphic on rice paper's not bad either.
The glass was another story. I am finding out that glass and epoxy work is fickle. It requires expertise and experience. Sadly, I have neither, yet
I am trying to apply the glass in the wooden press. I have read that it is possible, but frought with inconsistency due to the variable pressure in the press. For this project, I created the pressed blank first, then repressed a layer of glass, using an extra free layer of BB and some Polyethylene 6mil, for the under side. There were some inconsistent areas and bubbles, as well as some waves. IMO, it was all a result of pressing the glass after the blank was created.
For the top, I used glass as well, but layed it out surf style, with a credit card. It looked great until I applied my sand grip while the glass was still semi wet. In a few areas, where there was too much sand, some of the epoxy was absorbed away from the glass cloth. Then I applied polyurethane, which yellowed the purple color.
Finally, for the under side, I attempted a "hot coat", but found that the epoxy was too thick to level off. I squeegied it, but couldn't quite get the smooth texture I wanted.
Still came out looking pretty good, and it performs like a champ. I had never stepped on an LDP deck (other than one of Bryan's foam LDP decks with 8 wheels for a few minutes), but found that it was quite easy to generate speed and momentum. I have so many questions now regarding LDP setups and such, but that is for another time.
The deck has one layer of 10 oz E cloth on top and two on the bottom, with US Composites' regular epoxy resin. They recommend that glass for an all around balance of weight, strength and price. I believe they are right on.
Next time around, I am going to lay the epoxy and TBIII together, pressing all layers in unison. I am going to use vinyl as well, instead of the poly tarp stuff. I truly believe this can work, to create a decent glassy finish. I'll give it a chance, and one way or another, I'll find out if it will work.
Any advice or direction would be greatly appreciated. Specifically, regarding FG work, without the use of a vac bag, or board design.
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Last edited by hoch92000; 09-22-2008 at 10:02 PM..
In my opinion, it seems IMPOSSIBLE to get a full gloss, bubble and wave free finish if you are using a wood press....I still get waves even with a vac bag sometimes.
Another material to consider laying up against is mylar or PET. Get it in around 0.5mm thick, and it works like a charm.
I'm currently working on a system to get rid of bubbles from underneath the glass, and I'm getting pretty close with a vac bag... It involves laying up the ply as a separate "topsheet," and using a number of small holes on the bottom to help let the bubbles out.
Why not just upgrade? Setting up a reasonable vac rig doesn't have to be hard or expensive. There is a ton of stuff out there... I'd be more than happy to give you some pointers, as I went through the process myself a while ago.
Why not just upgrade? Setting up a reasonable vac rig doesn't have to be hard or expensive. There is a ton of stuff out there... I'd be more than happy to give you some pointers, as I went through the process myself a while ago.
I appreciate your comments and encouragement. I guess I'm just a stubborn old man. You may be right in the end. I'm going to have to see this one through though. Thanks. Sounds like you are using a perforated peel ply. I've heard that is key to get the bubbles out. Mylar seems stiff. I'm going to try the vinyl.
Mylar is stiff, but its super glossy. It helps to keep the waves to a minimum and is generally good at keeping bubbles out too.
You can do a layup by hand this way, just apply the fibreglass to the mylar, stick it up against the ply and work the bubbles out by hand. It works ok, its just far easier to do it in a bag...
Here is my trick for smooth glassy finishes. Coat the surface with resin, lay glass, re-coat with resin, work out any bubbles, let it cure fully, use a DA sander to smooth the high spots, use a few successive grades of paper, add a final layer of resin and let it layout nice and smooth, successive grade sanding and wax/buff like a car.
That gets it for me. If you want to paint it, do it after the first prep sanding and use flex additive. You could end up with quite a hotrod...
Mylar is stiff, but its super glossy. It helps to keep the waves to a minimum and is generally good at keeping bubbles out too.
You can do a layup by hand this way, just apply the fibreglass to the mylar, stick it up against the ply and work the bubbles out by hand. It works ok, its just far easier to do it in a bag...
I think part of the reason my pressed glass had waves is becuase of the stiffness of the poly I used. It is a gray/black thicker product. When stretched over a concave/camber form, it did not give at all, leaving wrinkles. I believe mylar would do the same, even worse. With a concave only or camber only (or flat for that matter), it is not an issue. For my next endeavor, I am using a moderately thick clear vinyl. It should give and stretch a little. I have tried the technique you've sketched out with clear poly, with a decent result. It was described on a sticky by mauiskategeezer. It left a bit too much epoxy on the board though, which can really add weight quickly.
You're probably right about the vac bag. I just might end up there, especially if I am going with carbon.
Quote:
Originally Posted by Camel
Here is my trick for smooth glassy finishes. Coat the surface with resin, lay glass, re-coat with resin, work out any bubbles, let it cure fully, use a DA sander to smooth the high spots, use a few successive grades of paper, add a final layer of resin and let it layout nice and smooth, successive grade sanding and wax/buff like a car.
That gets it for me. If you want to paint it, do it after the first prep sanding and use flex additive. You could end up with quite a hotrod...
It is helpful to know the effort involved with creating that glass like finish. Do you wet sand when you are sanding? Is a DA sander a surface sander, and do you use it for all succesive grades?
When I let the epoxy "lay out" on its own for the top layer, I found that it was too thick, and had to squeegy much of it off. Is this the prefered method, or is the eopxy heated or thinned out to make it less viscous.
Art, it looks good! From those pics its really hard to see the inconsistencies you are talking about and as long as it rides well and you learn what not to do next time its a success!
I think you are on the right track with getting a nice non-vac bag finish. The wood ply to even out pressure and a shiny flexible release film sound like they will work. You could even try some of the blue plastic perf film and a couple layers of heavy duty paper towels (without the print, like blue shop towels) to help with the excess epoxy problem. It won't be as smooth of a shiny surface but the final product would be lighter and it might help reduce the wavys between press ribs.
I have to agree that a vac bag is ideal here and my ultimate goal with composites is not having to anything but drill and trim/seal the edges out of the press. I have not reached perfection with that yet though as my finishes still have a small wrinkle pattern from the paper towels over the release film. A way around that is to use the bag film directly on the composite surface, but one has to be careful to get the excess epoxy (and air) out. I'm going to try it again on my next board the same way that WeFunk described in his thread about the speedbone.
Keep it up with the trial and error. You will land on something that works for you I think.
Bryan
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Thanks Bryan. Your words mean a lot. The vac bag with the perforated peel ply seems to be the best product. A friend of mine is in the airplane production industry, and that is pretty much what they use, in combination with carbonfiber and a heat activated epoxy. Funny you should mention towels. I just went to Walmart, in the fabric department and got some nice smooth substantial fabric for $1.00 per yard (6 feet wide). It was in their discount pile. Hate to say it, but it ain't going to be used for clothes. I am thinking about layingout over the vinyl to help even out the pressure. They sell the clear vinyl there too. $2 per yard (54"wide).
Like I said, I am going to see this through, and decide if the process works. I have some other ideas to which this might apply. For example, I am curious to see if this pressed glass technique would work to shape a V-lam - first glued flat then pressed with glass to get some camber/concave. I know lettucefresh describe a method of glueing the V-lamstrips and press into shape simultaneously. My proposal would be a bit different, but may not work at all. We'll see.
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