Seatback Cuts

[Blackhawk D]

It looks like the plans call for both sides of the seatback to be glassed and allowed to cure prior to cutting the center holes. In fact, it looks like one should glass one side and allow it to cure prior to the corner/side notches being cut.

 

Any reason all of the cuts can't be made prior to glassing and then trim (knife cut stage) the glass prior to cure? Sure seems like it would be easier to cut unglassed foam based on my limited experience from the chapter 3 practice layups.

 

I've searched the archives and this site and cannot see where this is addressed. Lots of discussions on whether to cut now (chapter 4) or in later chapters and on glassing/not glassing the seatback edges, but I can't find a discussion on cutting the foam prior to glassing.

 

Some of the builder's sites have the holes cut, others don't but I can't find an example of the cuts being made prior to glassing.

 

Any advice would be appreciated.

[John Slade]

Darrell,

I'm not sure where you're reading (or inferring) instructions to glass one side, then cut the notches. I cut the foam first. I think most do. I seem to remember cutting the map pocket hole after the first side cured, but I'm not sure. Cutting a hole in the glass after cure requires a little care. You dont want to delaminate the edge. One easy way is to use a handheld (yes - no handle) hacksaw blade at a fine angle to the glass using a straight edge as a guide. You'll find that the hacksaw blade will score, then saw through the glass without disturbing the edge. Don't use a jigsaw to cut a composite part - it'll rip the glass right off the foam.

 

A tip regarding "knife trim stage". Sometimes this occurs at 3am. You don't have to wait up. Just warm the edge with a hair dryer or heatgun the next morning and it'll knife trim just fine.

 

Now would be a good time to try the "plastic peel ply" method described on my web site "tips & tricks". You'll never regret it.

Regards,

John

 

PS - Never knife trim towards you. I know. I was that soldier.

[dust]

All of those holes you cut in the side of the seatback, so nice and perfect on the bench, not to worry, when you tape the fuse together you will cover them up and have to re cut them with your new best friend, a dremmel or other BRAND small rotary cutter.

 

he he he

 

enjoy the build

[Blackhawk D]

John, thanks for the sawing tips; I was considering the use of a jigsaw. I'll cut the foam and then glass. By the way, after a great deal of time reading your site, I have decided to wear a bright yellow "Florida" shirt while building. The shots of the palm trees and hot tub are inspiring for a western Va. resident! It feels like I'm on vacation just putting it on.

 

And Dust, "Enjoy the Build" I will! After 20 years of Army flying, I find the act itself a bit of a bore, but building - that gets me smilin'. Yours is a great tag.

[Bongo]

Excellent question Darrell! Bongo have same problem. I think they call it the “Assumption of Prior Knowledge Syndrom.” I was looking forward to hitting Chap 4 pretty hard this weekend. Bongo stuck scratching head, eating banana’s, re-reading plans and looking at other web sites. “Where’d those holes come from”....”nothing in the plans about holes” Maybe Bongo not read right. Read 4 again Bongo...nope...there’s those holes again. Get banana and read again! Look at site and find other builders having the same problem. Emm...who’s that guy that said the plans were easy again? We need to have a sit down. Hmmm...make mental note to buy a case of Dremmel cutting blades. Keep on truckin!

 

Bongo

[Jon Matcho]

“Where’d those holes come from”

The holes are for the control rods, and you don't need to cut them in chapter 4, but you can. I am holding off from cutting them since they're not required for assembly, and I plan to cut the holes where they need to be when I get there (to account for slight adjustments).

 

Here's the order that I did it:

• Make the corner and edge cuts.
• Glass the bulkhead per plans.
• Make the map pocket cut with the Fein brand cutting tool (get this immediately if you don't already have it)

[Spodman]

I dunno, I'm planning to do it as per the plans. Glass front side of the rectangular piece of foam, with one edge bevelled & rounded. Cut all the notches on the edges, round & flox corner. Glass the back, cut the middle holes later.

 

Don't think it's all that important if you do it a bit different, but note my opinions not yet tested by building anything.

 

One thing I note (in the aerocad plans) the last para of step 2 says

After part cure, knife trim where possible. The thicker buildups can be trimmed after cure with a sabre saw or hack saw blade.

Does this mean the BLADE of either a sabre saw or hack saw can be MANUALLY scratched at your bulkhead to trim, or can you USE a sabre saw?

 

Also, is a sabre saw the same as a jigsaw?

[Jon Matcho]

I dunno, I'm planning to do it as per the plans. Glass front side of the rectangular piece of foam, with one edge bevelled & rounded. Cut all the notches on the edges, round & flox corner. Glass the back, cut the middle holes later.

I guess I did it per plans then.

 

One thing I note (in the aerocad plans) the last para of step 2 says...

Guess what? That's the same text as in the Cozy plans.

 

Does this mean the BLADE of either a sabre saw or hack saw can be MANUALLY scratched at your bulkhead to trim, or can you USE a sabre saw?

Manually cut by hand, or better yet, invest in the Fein Multimaster tool.

 

Also, is a sabre saw the same as a jigsaw?

I thought so, and half of me still thinks so, but my tool-oriented friend tells me that a sabre saw is more like a "Milwaukee Sawzall" -- certainly not something I'd use to build with.

[Daniel Dillon]

I am just getting started and will be caught up to this point in no time. If you could post your conclusions to this question, it would be appreciated as I will have the same questions. Let us know how yours turns out.

 

Dan Dillon

Cozy MK IV #1353

 

It looks like the plans call for both sides of the seatback to be glassed and allowed to cure prior to cutting the center holes. In fact, it looks like one should glass one side and allow it to cure prior to the corner/side notches being cut.

 

Any reason all of the cuts can't be made prior to glassing and then trim (knife cut stage) the glass prior to cure? Sure seems like it would be easier to cut unglassed foam based on my limited experience from the chapter 3 practice layups.

 

I've searched the archives and this site and cannot see where this is addressed. Lots of discussions on whether to cut now (chapter 4) or in later chapters and on glassing/not glassing the seatback edges, but I can't find a discussion on cutting the foam prior to glassing.

 

Some of the builder's sites have the holes cut, others don't but I can't find an example of the cuts being made prior to glassing.

 

Any advice would be appreciated.