bubble doors

[Flybyjim]

I am going to start mounting the bubble glass to the door frames tomorrow, any advice out there of what to watch for and things not to do.

[Esser]

This one is pretty obvious but really make sure you get rid of your acrylic shavings before pulling the 3M tape out. I didn’t do this and I have white stuff all stuck to the black tape which doesn’t look great.

I can’t stress this enough, do not over tighten the screws. The tape holds the door on. The screws are just a mechanical fastener. You basically want to go finger tight and then a 1/4 turn. Anymore and you are likely to crack the acrylic.

[Flybyjim]

Good point, I am concerned with making the cuts, these doors are oversized a lot and I am going to have to cut the top off to even get into any alignment for the other dimensions. I am planning to cut it with a fine tooth blade band saw to start and finish with hand sanding. It seems to me if I cut away too much at the top of the door or do not cut it at the correct angle I am going to be ordering a new door. I do not want to go there.

[Esser]

I went through his too. Go slow and it makes sense. I started by getting the first cut out of the way off the top of the door. In hindsight, I did cut off too much because the bottom of my hinges hit where the bubble started. I rounded the bottom of my hinges to make it work so all the pressure wasn’t in one spot. I hope this makes sense. You can avoid what I did by basically putting your hinges on so they lay flat and make your first top cut in reference to that.


Secondly, I put the door frame in with the hinges. I held the bubble door up with a hand from my wife and marked where the holes for the hinges would go. I drilled those holes in the acrylic door, and then took strap cut off acrylic and drilled another hole. I then attached my door to the hInges with clecos using the scraps as a sacrificial piece that would take the stress. So it would be hinge, bubble door, scrap clecoed together in that order. No door frame at this point

With the one half of the hinge permanently mounted to the fuselage, I used 3/32 drill bits as temporary hinge pins. I would hold the door up, put the pins in the hinges, and then I took a straight edge and drew the edge of the door frames onto the bubble door, I’d unpin the door, lay it on the table and trim with an angle grinder. I would then put the door back on to check for fit and do it again.

Maybe not the best way but it’s what I did and it worked out well.

[Flybyjim]

Thank's Josh,

The top of the door glass, did you try to make that even with the hinge line of the door hinges? Or did you keep the glass even with the door frame? It seems if you go higher there would be binding of the glass.

[Esser]

I went to the top of the flat part of the hinge. I basically tried to have enough acrylic so that it covered the gap between the door frame and the fuselage to help elementary drafts.

[ken nougaret]

Do not use loctite! It will cause crazing.

[efwd]

Apply the adhesive tape to the door frame. Leave the backing on the tape that will adhere to the bubble. Have all the holes drilled. use a few screws to have the glass aligned and while the glass is on, peel the backing off the tape. It can be tight but you can peel the backing off while the glass is laying on the frame.
Eddie

[aviator79]

I'm far away from that step, but in another thread someone recommended using a bandfile for final shaping. I had never heard of this tool before, but bought one at Harbor Frieght when prepping for my kit, and it's becoming a favorite tool. Very nice for shaping anything (false ribs under the tank, fuel sight gauge plates, and I assume door acrylic.) Fills the gap between Dremel and belt sander nicely.

[efwd]

LOL, if your trimming acrylic on the door then your much closer to that step than you think. Sometimes steps seem distant but before you know it a couple hours later your finished with the part. Those are the times that you realize the build process is gratifying from start to finish. Kitplane magazine had an article once that reminds you to not go into the shop saying "Im building an airplane". When you continuously come out without an airplane youll become discouraged. I live the process of building parts/assy's etc. I am frequently pleased with a days work.
Eddie