rbrown7713 Posted July 22, 2017 Author Share Posted July 22, 2017 Well, at least I know now that epoxy mixes with urethane, but it doesn't do anything but set me up for a mistake. Bob. Quote Link to comment Share on other sites More sharing options...
Screwy Nick Posted July 26, 2017 Share Posted July 26, 2017 Bob, anxiously awaiting your progress. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted July 26, 2017 Author Share Posted July 26, 2017 I am laboriously continuing my work on the T1. I am presently making the side fairings and also installing rivets, took me a day just to figure out how to properly program the right and left sides, but it is programmed now and today I have made a Bondo mold base to cut them out in. It's nice to have a cnc mill. Here are some pictures before the machining of the sides. The white piece is of the first attempt for the fairings, but I would have to installed real little rivets and it is much easier on the mill. When I get it machined, I will post a picture and then the actual part with the rivets. I now have enough urethane to pour another shell and will do so shortly, then marker lights, some more detail and then final assembly., I will be happy to finish this project as I have other things to accomplish. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted July 27, 2017 Author Share Posted July 27, 2017 Well, one of my last comments was, it's nice to have a cnc mill. Well, it's not so nice now. Won't boot up, so I will be down for a while until I fix it, so I will let you know what happens. Bob. Quote Link to comment Share on other sites More sharing options...
Chuck Posted July 27, 2017 Share Posted July 27, 2017 Won't boot up...ugh...do you have to write all the g-code and if so do you have a back-up copy?? Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted July 27, 2017 Author Share Posted July 27, 2017 Yes, I have copies of the programs, but when I say it won't boot, I get a screen, but there is no message lines so I can't engage the servos, so I checked the limit switches and they are good, so somewhere there is an open in the servo check circuit. I have contacted Anilam and they are to get back to me and they have been very helpful in the past. Last time it was a drive board, but this time, I think it is something else. The chief tech guy is a genius and he will know right off what it is. I am waiting for his call. Bob. Quote Link to comment Share on other sites More sharing options...
Screwy Nick Posted July 27, 2017 Share Posted July 27, 2017 Bob, I am very sorry for the problems you are having, if their tech assistance is anything like APPLE, you are in good hands, IMHO. Since you mentioned Bondo, I am about to have some fun with Bondo Glass. Part of the FRP hull is supposed to have PVC strips installed as bulwark. nothing more than to make it smooth. Near the bow I can't seem to make the strips they included for that make the compound curves necessary even with heat. I decided I can use the GLASS compound for that area and also fill in minor blemishes as well. Any advice you can offer me for this part will be greatly appreciated. LG Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted July 27, 2017 Author Share Posted July 27, 2017 It sounds like you are on the right track, can't add anything to that, just make sure that, if you can sand the area to be used. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted July 27, 2017 Author Share Posted July 27, 2017 I think my problem is solved, but won't know until I install the new board. I will get it in about 5 days. I talked to Anilam and they helped me identify the bad board and ordered one, 118.00, not bad, as the previous board cost about 400. I have some other parts to pour, so I won't be slowed too much. Bob. Quote Link to comment Share on other sites More sharing options...
enginear joe Posted July 27, 2017 Share Posted July 27, 2017 That could sound like a lot of money. If that includes his tech work over the phone, that is a deal. I would like to have that kind of customer service for everything! Good luck!.... ur um,... I mean, break a leg? Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted July 27, 2017 Author Share Posted July 27, 2017 Break a leg?, I stubbed my toe yesterday and had to call a toe truck and it cost me an arm and a leg. Bob. Quote Link to comment Share on other sites More sharing options...
enginear joe Posted July 27, 2017 Share Posted July 27, 2017 It's a show bizz thing. Good luck may mean a bad performance so they say "break a leg". ( I know it's backwards) Toe truck is expensive? Good thing it wasn't an arm and a leg.....truck. Quote Link to comment Share on other sites More sharing options...
Screwy Nick Posted July 28, 2017 Share Posted July 28, 2017 Bob, thank you, I'm hoping for the best. Last time I used Bondo was to patch a storm door, I learned to use as little harder as possible. Yes, I did sand the area that I'm going to fill. Happy your on the way to solving your problem with the system. Stay Well EDIT: i just applied the first area, not quite all the way but am satisfied with how it came out. The 'hair' in the compound made it a bit more difficult to mix and apply as it had a tendency to draw more off than I wanted, but I'm learning and happy with it so far. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted July 28, 2017 Author Share Posted July 28, 2017 You might already know this, but I will relate anyway. Some differences in epoxy resin and polyester. I use epoxy for my molds because of several reasons, one, I have much more working time as the curing time is linear, no surprises. Polyester, depending on the amount of catylist used might surprise one with the time of hardening, no surprises with epoxy. Also when using polyester over polyester, there is a chemical bond, not so with epoxy, purely mechanical, so sanding is a necessity. Also, lets say I am using epoxy resin for a layup with glass, If I take too long and it starts to gel, I can take a heat gun and blow it on the area that is gelling and it will become less viscous and allow me to finish the layup don't try that with polyester, it might catch fire. Also when making a mold with detail, just laying glass over the details won't work, one will have bubbles because the glass is stiff and won't take the form of small irregularities, so I first mix glass spheres, micro balloons to a peanut butter consistency and spreading the mixture over areas of detail the would cause a problem if not used. Then I lay glass over the entire area and then no bubbles. There is another advantage of using epoxy, fewer things will stick to it, good when using plastic for the part. Also, epoxy is more stable, maintains shape, once cured and less shrinkage Here is a picture of one half of the shell for the T1 and you can see where I used the micro balloon mixture, the light areas, and none on flat surfaces because the glass will lay flat where there are no irregularities, the whole aim in making a mold is, no bubbles. Of course, I wax my molds several times, maybe 5 times with mold release wax, Maquires No. 8. Even after waxing, when making the part out of plastic urethane, I spray it with silicon release. One problem when using silicon, is it is difficult to remove the silicon on the part for painting, haven't quite figured that out yet, but I am working on that. Just some of things that I have learned to do when making molds or parts. Bob. Quote Link to comment Share on other sites More sharing options...
Screwy Nick Posted July 28, 2017 Share Posted July 28, 2017 tBob, thank you for sharing your years of experience with us. I know I will not retain what you have posted, but I will print it so I will have it when I need a reference. BTW, learned that I need to use Bondo #3 as a finish coating if I want it to be smooth. Never too old to learn. Stay Well Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted July 28, 2017 Author Share Posted July 28, 2017 Like I said before, I don't know how many forum members make molds, but since I have made molds before, I feel like sharing my experiences so that some might benefit. You might have noticed that not only trains is a part of my hobby, molds are a big part of my hobbies. By the way, I have finally came up with the plan for the inside cab portion of the mold to make it easy to remove the inside of the mold. I will use three 1/4 inch pieces of plywood approx. 2.5 inches and place them side by side with a longer one in the center of the three. Then when demolding the center mold, I will pull the center board out, leaving room to remove the two pieces of wood from the mold. At this time I can bend the sides of the center mold back from the under cuts of the part, easily removing the urethane mold without worrying about mold lock. It will make more sense when I post a picture. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted July 28, 2017 Author Share Posted July 28, 2017 This time, the shell came out great, no short pour. Bob. Quote Link to comment Share on other sites More sharing options...
dieseldude Posted July 28, 2017 Share Posted July 28, 2017 Cool! Looks like a big white chocolate T1! Can't wait to see some wheels under it. -Kevin. Quote Link to comment Share on other sites More sharing options...
enginear joe Posted July 28, 2017 Share Posted July 28, 2017 Hmmm, a mold made from white chocolate....can I eat it later after I pour? Quote Link to comment Share on other sites More sharing options...
Screwy Nick Posted July 29, 2017 Share Posted July 29, 2017 Bob, looks great, and thank you for sharing your experience and knowledge with us. LG Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted July 29, 2017 Author Share Posted July 29, 2017 Your welcome. Again, I am not sure how many people can use this info., but I will try to relay as much as I can from things that I have experienced and if anyone has any questions I will let you know how I do it, not that my methods are gospel. Here is the situation that I was talking about with the protruding window. There has to be a means to remove the inside mold section after pouring or there would be mold lock. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted July 30, 2017 Author Share Posted July 30, 2017 Here is what I have been talking about. The 1.5x2 inch displacement board is in place and after the pour will be removed to allow the center mold section to be removed easily. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted July 31, 2017 Author Share Posted July 31, 2017 I poured the last section of the cab mold and will try to pour a part tomorrow or the next day. I think the mold will come out perfect for a good part. Bob. Quote Link to comment Share on other sites More sharing options...
rbrown7713 Posted August 1, 2017 Author Share Posted August 1, 2017 The mold came out good and was able to remove the pattern with minimal damage. Bob. Quote Link to comment Share on other sites More sharing options...
Screwy Nick Posted August 1, 2017 Share Posted August 1, 2017 Bob, BEAUTIFUL, watching this all come together is almost as good as doing it myself. Quote Link to comment Share on other sites More sharing options...
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