10' Standie Foamie ... on hold

[GPW]

Next Spring ??? Na Unh !!!! That'll take Forever....

Mike the old school method is to make a cardboard template with the radius you want and just use that to measure your progress... sand and fit ...

[mikeschn]

That's as good as it gets? A cardboard template?

Mike...

[Wolffarmer]

Well, you could transfer it to sheet metal



Randy

[Verna]

Besides I am trying to decide how to round over the outside edges, with a little more precision than just eyeballing it.

Mike...

Well, Mike, it would be possible if you could form a "Sureform" hand plane blade into the round-over radius you want. Then put it in a wooden jig to hold it in the same position for every edge.

Just a thought.

Sureform Plane

Verna

[Wolffarmer]

Hmmm, I wonder what a cabinet scraper type of template would do on foam.

Randy

[GPW]

Mike ,the scientific method would have you drawing parallel lines a certain distance from the edge each way (X) then a flat would be cut/sanded between those lines , which would give you 3 edges ... then draw parallel lines on the center 2 lines as before ... cut/sand those away , now you have uniform 5 edges ... You see where I’m going with this ? You end up with a round edge if you repeat this process to infinity , but you can just sand the rest once it gets sorta’ rounded ...
Wolf , it don’t work ... tried it , made a mess...

[Wolffarmer]

Thanks GPW for your trying that first. Save me the trouble.

Randy

[atahoekid]

I've got the same issue as Mike. I was thinking of doing it the way that GPW mentioned but I was going to use a wood template to try to do a bit better than eyeballing it. I was also thinking about sharpening a scraper and seeing if that would work (apparently not). I'm stuck for a better solution at this point except judicious use of the random orbital sander and some long fairing boards (diy) and constantly checking progress with a template of the proper radius.

[tjsabo]

My thought is take two boards 4"W x 12"L screw them to form an angel 4 x 4 x 12 then use bondo to make the radius on the inside then line with sand paper

Tim

[GPW]

Foam is so EASY TO WORK , Simple to just sand it and match a template ... I did mine with a belt sander ... Tricky , but Quick !!! No measuring , just by eye... Worked !!!

[crumbruiser]

I vote for the belt sander!
Frank

[GPW]

Gotta’ be CAREFUL with the belt sander , a light touch or it will EAT into the foam where you don’t want it to ...

[pete42]

I'm not really sure what you are rounding over we used aluminum templates and hot wire to cut the leading edges of the wings when we built our all fiberglass airplane,
we had two templetes one on each end held on with brads there were numbers when using the hot wire one person on each end one saying the numbers: 1, half, 2, half, 3, half moving the wire at a slow but constant pace
when we reached the leading edge the numbers were closer together but the cutting speed slowed so as not to drag the wire in the center and cut a bow wish I could post pictures.

[RAYVILLIAN]

Mike some thoughts on your accurate curve problem.

1st the many straight lines make a curve. Make a jig with the foam cutting wires could be set up at 45 degree than 22.5 degree the 22.5 could be used twice once from the side than again from the top. You could take it to 11.25 but with the small curve you'll be working with I don't think you need to.
Than make a curved sanding block fastened to a vibrator sander to finish the curve.

Just a thought.

Gary

[aggie79]

As far as the radius, how about using a piece of PVC pipe? Using a tablesaw, you could rip a 90-degree slice of the pipe. Attach sand paper to the inside radius of the sliced pipe. This would give you a profile.