The plastic wrap was a bad idea for a concave shape. It wrinkled a lot, and some of it got trapped in some resin around the edges. When I trim the flashing, and sand it, it should all be OK, but that's a lot of work. I never thought to practice working around reinforcing rods, I just sort of assumed it would work OK from the project logs I saw where they did something similar. It may have been the cloth that was at fault, it wanted to straiten itself out from the get go. I figured it would all set there OK, so I didn't plan on using any weights. That was a bad idea. If I had cut something to sit between the rods I wouldn't be left with some of the resin bumps I have now. Those bumps are the result of the weight forcing resin out from the cloth (which soaks it up like crazy), and into the voids of my hasty cardboard job. One strip has also become part of the piece It's still tacky so no pictures yet. Once it's fully dry, I'll take some naps of all the pure ugliness. If I recycle it into a case piece, I think sanding will fix the issues after trimming the excess, but I'm just a bit disappointed in my lack of foresight. What I have learned is I need to try and do something more 3D instead of just trying to make panels that I bond together. That eliminates the need for reinforcing rods. So I need to get some styrofoam, and tape (no idea about what wax I should use, if any). It should make things a bit more interesting.
With the styrofoam you shouldn't need to add anything to it. To get rid of the foam (If it sticks) use petrol to dissolve it. Can we get some pics of the process?
I was trying to wait for the piece to cure and stop being tacky (no puns please ). I thought I had more than enough hardener in the mix and figured it had to do with the platic wrap. So I removed as much as I could and let it sit, ater 48 hours it should be fully cured. So I gave up and here are pictures of teh ugly. I don't know if the separation of the fiberglass from the dowel can be seen in the pictures. I tried soap and water to see if I could wash some of the tack away, and water found its way underneath the fiberglass. I'm still baffled as to what the right way to do this is, but I think some sort of mold system with styrofam is the way to go. But, once this is cleaned up a bit, I should be able to use it for airflow testing and basic design testing.
Those look quite good, a little rough but still good. For the mould just get a block of styrofoam and cut a rectangle out of it and pour the fiberglass in on the mat. There is a way you could make it a single piece apart from the side(s). Get a block of styrofoam and cut your top, bottom, front and back "panels" into that block and then slide the mat into the gaps and then pour in the fiberglass.
In the third picture on the middle stick, you can see where the concoction wanted to pull away from the rod and delaminate. It is quite strong in the direction of the rods, but not quite as good in the other direction, the lips don't provide as much reinforcement as I hoped, possibly due to their low quality I'm sure I'm not alone here in being a perfectionist, so I'm going to take another crack at this. I can use what I have now for the airflow and temp tests I want to do both for the arrangement I've posted, and the new one I've come up with this week (much more compact, but may not get enough airflow). I really want to know why the fiberglass puled away and tried to 'flatten' itself out. With all the fiberglass work done here that I have read the logs of, I have not seen an issue like this mentioned. I think I may need to start a new thread specific for that question. edit: A short encounter with a 250 degree oven seems to have removed the tackiness. Sol it seems the cold, damp spell where I'm at really affected my cure rate.
It looks to me like you are using too much resin. If it were me, make a mold in pretty much any material. Then cover it in something like filler and sand/polish it smooth, then put a releasing agent on it, eg wax or PVA glue (pva is good if you cant seal the mold, but you have to re apply each time you use the mold. lay a thin layer of resin,(if using gel coat, thin layer, let it go tacky, then the resin), then straw matting then push the matting into the resin with a roller, or similar, you need to remove all the air, the resin should have all been soaked up, so add more resin, more matting, roll etc etc till its all done. Let it set, then remove from the mold with wedges, water etc etc. Andy
@AndyFielder Thanks, I'll try it out this weekend. I'm assuming any hard surfaced roller will do, or is there some tool in particular? I have been using the standard bondo resin I can pick up at the auto parts store, is there anything better? @AFX It's a 50". It's a little over sized for my small apartment, but I intend to move into a larger place so I bought something a little large. The only complaint I have is that the vertical viewing angle isn't the best, it can be a little hard to see when I'm standing up playing Rockband or Guitar Hero. But it would be OK if I could stand back further Is there a good place to get more info on he tools and procedures for working with fiberglass?
It the hlt5087sx, the LED backlight and color reproduction are what drew me to it. DLP is the cheapest way to get 1080p. The size is a compromise in budget and room. My couch is about 11 feet away from the set, which is about the closest it can be comfortably watched at. I'm hoping to move to a bigger place once my current lease is up, so I wanted the set to be able to work with a larger room. I don't think 67" would have left me with any place to put my speakers, or AV equipment I won't be using that panel for airflow testing, it's warped enough that I couldn't get the board mounted to it. So I decided to see just how strong it was, I raised it up between some phone books and stood on it. I'm amazed it held up until I jumped on it. I'm 6'4 and on the heavier side. I'm going to saw it in half in later to show just how bad a job I did. I'm going to go back to the system I was using to make flat sheets. I have some fairly heavy guage sheet metal panels from an old case I've been using, and pressing the layers in between them. Once they are mostly cured, I will add the dowel and other layers, but I will use a mold for that to make sure the fiberglass conforms to the dowels. If that doesn't go well, I think it's back to the MDF plan.
<drags self back into forum> Been a bit busy with things other than this. I did start another attempt, using the roller to press the random fiber stuff into the previous laer does seem to get nicer results, but I'm having a problem with the strands coming up and sticking to the roller. I only got about half way through the next attempt before having to put it aside, so I'll try to get pictures up in the next day or so.
I'd suggest applying as much pressure as you can apply evenly while the panel cures. No kidding, only $2499.99 at the theater store in my town... hard to resist.
Water is bad for fibreglass that's curing, it goes a funny white colour and won't cure. The oven is definitely the best way to cure it quicker if you want, just be careful it doesn't catch fire. Epoxy is the best stuff but is more expensive. Polyester resin is good cheap large quantity stuff, but will melt foam.
Umm what ecaxtly are those panels for? Because they look rough! Your going to give yourself way to much finishing work! You need a mould! For flat panels a sheet of mdf (waxed) or a heavy window pane (rubbed with talcom powder) would work good! styrofoam is not a great idea as it will melt! Epoxy resin is not worth the price or hassle. That tackiness is normal its actually needed when working with layers! Its a result of the stryene evaporating as it cures. The only real way to get rid of it is with a topcoat. Or a very long time!
