Scale Wendell Hostetler 30% Piper Cherokee Glass Fuselage Build.

Seen this on line, used to eject the part, some molds have a hole where a blow gun is used, the valve stems will provide a positive seal. It is always a pain pulling a part out of a one piece mold. The valve stems are located on the areas that will cut out so no worry about making a mark on the finished part. Itis a first for me. I actually considered mading the mold two piece but didn't have a suitable parting board.

TonyHallo said:

Seen this on line, used to eject the part, some molds have a hole where a blow gun is used, the valve stems will provide a positive seal. It is always a pain pulling a part out of a one piece mold. The valve stems are located on the areas that will cut out so no worry about making a mark on the finished part. Itis a first for me. I actually considered mading the mold two piece but didn't have a suitable parting board.

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Good idea it should help getting the cowl out.

Have the right wing root coped and the 1/8" lite ply rib glued on, once the wing incidence is set, the gap will be fill with Superfil.

Have the left wing coped and the lite Ply root rib installed. need to add plywood reinforcement circles inside the fuselage where the locating pins are located before I can set the incidence.
Put the last layer of 19 ounce cloth on the cowl mold, tomorrow I will test the air valves. Really not to sad this mold making is nearing an end. Have 40 ounces of cloth in the mold, should be OK.
Have the dash ready to send out, tomorrow I need to paint the yokes, going with white yoke and gray dash panel, should be nice just like the one below.

Got the plug out of the mold this morning, the valve stem would not do it alone, had to blow air into the back of the mold between the plug and the mold, once I did that and hit the first valve stem it popped out with a bang. It was the easiest one piece to get the plug that I have made, most of the time end up destroying the plug. Had a few areas to san out where the clay sealed the plug to the parting board, no big deal. Let the waxing begin!

Put the fuselage back on the bench to set the wing incidence, threw the wings on for a photo op. The door just barely clears the wing.
Have seven coats of wax on the cowl mold, might be ready to lay up today.
Shipping out the dash foam and yokes to SAC today to get price quoted. Pretty sure whatever the price is I'm going for it! This will the third dash they have made for me. They are making the emblems for the yokes as well.

When I build a wood plane, the wing aligned holes are drilled with the sides together so that a long drill can be used through the fuselage to drill the holes in the wing,this keeps the alignment pins parallel to the wing tube. This is completely different way of building so I had to come up with a way to align both sides. Not sure why a saved this scrap of Formica from the wing root template but it came in handy. Both side are drilled and the 1/4" plywood circular reinforcements are epoxied in. Have an 18" long 1/4" drill bit for this job. The front pins will have 1/4-20 threads on the end for the retaining nuts.

Got the cowl laid up. Put on 3/4, 1 1/2, and 4 ounce this afternoon, came home from my grandson's basketball game this evening and put in the 6 ounce cloth. There's over two hours of layup work on it, don't know how the fiberglass folks can sell them so cheap! There's a lot of fiddling around on the air inlets and the headlight depression. When I wake up for a nature call tonight, hope to come down and trim the mold while it is green, 6 hours is about the perfect time with the medium hardener.
Took a count today and determined there are 12 molds for this build plus at least one oops mold! I think I'm done making molds for a while.

The ‘photo op’ brings the story home. Wow, what a project…

Woke up last night at 3:30 and made it down to the shop to trim the cowl, was just about the perfect time, maybe another 1/2 hour would have been better. Decided to put a little heat on the mold to speed the cure. Inverted the cowl on the 12" disc sander and placed a 1500 watt oil filled radiator under it about a foot away. Heat will rise into the inverted cowl and gently heat the lay up. Back to bed. Woke up at seven and made the coffee, wanted to sit down and surf the web but I was like a kid in the candy store, took my pills with a little tomato juice and went to shop, started the air compressor on the way down, still had about 60 psi from the previous use on the plug. The mold was about 100 degrees and the layup felt cured, no tack. Blow some air around the back side joint and could see the cowl seperate form the mold, did all four sides flip it over and hit the middle valve stem, pop! Flipped the mold over and what do I see, the front side of cowl puckered in!!!! Got the cowl out and pushed it back into shape really didn't want to lay it up again. I can fix this.
Washed the mold and put another coat of wax on, then PVA. Sanded the exterior and interior where the creases were, when the PVA was dry painted the exterior areas with epoxy and pushed it back into the mold then put another layer of 4 ounce cloth on the creased areas inside the cowl. I didn't account for the epoxy not being fully cured and warmed up which soften the epoxy. Lesson learned, when using air eject leave it in the mold for 2 days. After cowl had cooled it was stiff so I'm sure the repair will work out.