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Old 10-04-2017, 01:17 AM   #1
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Default Fiberglass Mold help

Ok I picked these molds up on the way to Oshkosh. They were suppose to be Fairchild 24 shape but are more like what is found on Stearmans and Wacos. Also like what Steve Culp used on his Culp Specials. I decided I really like the larger size. Very retro looking. My problem is the molds, as nice are they are were made with no flange around the perimeter. I don't have much experience with mold making but know that's the best way to keep the mold from "pulling in" or shrinking. Anyway there's a term for it I can't recall my question for you more experienced mold men would be are these molds fixable? What about if I use 4 layers of 7781 fiberglass, do you think I could pull the pieces into shape by using a piece of aluminum clecko'd around the perimeter and cut out the tire area...and glass the inside seam. Then after the inside seam is dry, remove the clecos (I'd dip them in Johnson paste wax, works very well. I've done a lot fiberglassing using that, light coat...wipe excess off so it doesn't contaminate the bond) and apply some filler to make the outside seam area the correct shape. Then lay a piece of fiberglass over the filler and seam so it won't crack. OR should I trash these molds and just buy the ones Wag Aero sells for $335 each ? IMG_4864.jpgIMG_4866.jpgIMG_4867.jpgIMG_4871.jpgIMG_4870.jpgIMG_4868.jpgIMG_4869.jpgIMG_4181.jpgIMG_4182.jpgAttachment 1
Any idea who "C Bennett" was? He might of had a Fairchild 24. I got these in Minnesota.


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Old 10-04-2017, 03:59 AM   #2
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Do you know if they are suppose to be butted together as is or if there is extra that is trimmed? You could bond a 3/8 ply flange around each mold and use it to pull it straight if the mold is to be used without trimming. If there is excess to those molds, you could put the flange where the edge needs to be and trim the excess off the mold. No matter, a matching ply flange could pull the molds straight.


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Old 10-04-2017, 09:36 AM   #3
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Don't know about anyone else, but I've never had fiberglass shrink during a layup. Charge ahead!
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Old 10-04-2017, 12:16 PM   #4
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I thought about trying to attach a plywood flange...but the molds move VERY little. As you can see in pics one is alittle worse than the other. So I could probably make the plywood lip based off the better of the two and maybe add a 1/8 to the opening. But in reality no I do not know if they are made to be butt joined like I have in picks. I just assume since there is no joggle and they are equal width. I'm just wondering if it's doable and "easy" to manipulate a 4ply half where this slight difference won't matter if I pull them together via the aluminum strip I mentioned before while glassing the inside seam? Really sucks these molds have shrank like they have. The shape is great and I know they weren't purposely made with the edges pulling in like they are. I have heard of this issue on molds before and I know to use a perimeter flange...I just wish the mold builder here would have also.
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Old 10-04-2017, 01:31 PM   #5
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If you think they might be worth saving, it's a lot of work, but less than making them from scratch.
There seem to be 2 issues, hard to tell from pics.
1. Looks like edges have turned in toward center in some places.
2. Edges of the 2 halves don't match up.
If you just had #2, I would think they didn't deform and are meant to be trimmed. Since you have both problems, they probably have deformed. I have seen fiberglass cowls deform badly with engine heat and stay deformed, so maybe....
If you think the edges should match,, then I would cut two identical plywood bulkheads and put one inside each half near the edge to force it out to the proper shape.
Then I would glass on some strong tabs so you can pull the edges together with bolts through the tabs. Some web or steel straps might help also.
Place the mold in an oven or makeshift heat box and warm it up till it gets flexible enough to pull together. Let cool and install perimeter and external egg crate stiffeners to hold the shape.
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Old 10-04-2017, 01:47 PM   #6
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Do you think I should cut the wheel opening out before I try and heat it up and install the perimeter flange? I thought that may help it "move" into shape. Right now you can't get the molds to budge. They are very strong.
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Old 10-04-2017, 01:48 PM   #7
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They look like a quickie mold called a splash mold. when you have an original part you make a light weight mold off and then use that to make a model or plug to make permanent mold
The way they are now if you made a part you would not get it out of the mold.
To use them you will have to open them up so they do not turn in
Being careful to keep the outer edge nice even flow. I live in the Southwest and when I do something like that I shim it out from the inside and set it in the sun you can use heat lamps but you have to be careful you don't overheat the mold and ruin it.
Once you get the edge out you would put a flange on it to keep them from going back in
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Old 10-04-2017, 01:55 PM   #8
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Tom that's the trick...getting the edges out where they need to be. Right now...unheated. They don't budge. Only way I see getting them out is making the plywood flange...attaching som hardwood blocks to the plywood and then drill the mold and use bolts to draw it open to meet the plywood perimeter. Maybe with heat this is easier than I'm thinking?
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Old 10-04-2017, 02:11 PM   #9
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Using Bolts like that with only pull out right where the bolt would go through and probably crack the fiberglass and then you would have a wavy edge
I would try putting a couple of 12 inch long one by two's on each edge and then a scissor jack in the middle to push out
Put pressure on set in the sun go back in a hour or two later and see if it feels like the same amount of pressure of the Jack is loose or semi loose it's moving for you do not want to push too hard could break the mold.
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Old 10-04-2017, 02:21 PM   #10
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Those are from a time when a lot of finishing work was OK. Today we want it done and light once popped out. You might try some type of spreader bar to push the molds out. You can always add a joggle around the perimeter. If you don't like how they come together, you can always get the shape close, fill it full of foam and make some new molds off the foam plug .
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Old 10-04-2017, 04:43 PM   #11
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I wouldn't cut the wheel opening until it's straight and reinforced, it might spring into a worse shape if cut now. You could make a bulkhead and remove a 1" strip down the center of it, then insert both halves (you would also need to remove some wood from the ends) and bolt strapping across them for alignment. Then as/if it heats and softens expand the bulkhead with wedges a bit at a time. As Tom said, they don't look like production molds, more a one off, if you are able to fix them you might want to thicken them up.
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Old 10-04-2017, 05:04 PM   #12
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Just noticed your other post I would not cut out where the wheels go
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Old 10-06-2017, 06:59 PM   #13
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I think would leave the wheel opening filler in place until the halves are joined. My opinion only, worth what you paid for it.
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Old 10-21-2017, 08:49 PM   #14
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Ok well after alittle more research I found a fiberglass company called Karg Fiberglass. They build the Stearman pants for Wag Aero. And also do Waco pants for either Waco Classics or Rare Air (all I know is he said he makes waco pants for the new guys)anyway...his prices are 1/4 of what Rattray prices are! Iíve ordered a pair of pants I think will be the perfect size on the Starduster Too (Iím using 22Ē diameter 8.50x6 tires) to give me the look Iím going for. If anyone is interested in the mold set I have Iíd sell them for what I have in them $200. ($100 for molds and about a extra $100 in gas to get them)

Check out the ones I ordered...what do yíall think ?IMG_5013.jpgIMG_5014.jpgIMG_5015.jpg
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Old 10-21-2017, 10:43 PM   #15
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They make the Acro Sport wheel pants for the 6:00x6 tires as well. I got a set of them through Wag-Aero because they wouldn't sell direct. Mine are going to take a little work but should turn out fine. They are heavier than those from Van's or other suppliers that strictly make airplane parts.
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Old 10-21-2017, 11:51 PM   #16
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1/4 th price sounds better to me!
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Old 10-22-2017, 01:48 PM   #17
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Be cautious. I bought a nose bowl from wag years ago, don't know who made it for them , maybe the quality is better now. The mold was made from a dented old bowl, the part was chopped strand mat, no woven glass, it weighed a ton. I complained and they said it said some sanding may be needed, it needed body filler! I sent it back and after paying shipping and their restocking fee, I had nothing!
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Old Yesterday, 03:16 PM   #18
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They had sent you a plug!
Chris...

Quote:
Originally Posted by planebuilder View Post
Be cautious. I bought a nose bowl from wag years ago, don't know who made it for them , maybe the quality is better now. The mold was made from a dented old bowl, the part was chopped strand mat, no woven glass, it weighed a ton. I complained and they said it said some sanding may be needed, it needed body filler! I sent it back and after paying shipping and their restocking fee, I had nothing!
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Old Yesterday, 04:07 PM   #19
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? no just a poorly made low quality nose bowl.
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Old Yesterday, 07:48 PM   #20
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Default Fiberglass Mold help

I was curious about weight as I know they will be chop fiberglass mat not woven. He weighed the one in the pic and itís about 7lbs. Alittle heavy I guess but pretty close to the Rattray ones for 1/4 the price. ($1000 EACH vs $250 each). Now that I have exactly the shape I want if I get real spunky I could make a nice quality mold off one and make some carbon ones...but that will only be if I need to for a drastic weight reduction program. My plane may be heavy, but it flew a lot of years and hours just fine. Iím shooting to loose 57lbs at least in the restoration...we will see. (It was 1556lb empty...again yes thatís Way heavy for a 0360 Starduster Too but not crazy for a 540, Ranger or Radial Powered one from my research. I know of a Jake powered one that flys great at over 1700lbs. And I know Kevin Shawís 220 continental powered one flies great now and it was exactly 1556lbs) my old AcroSport 2 had the Wag Aero Acrosport wheel pants and they were heavy but they didnít have any cracks...


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