Wes' teardrop - Fiberglass finished Bondo started - Page 9

[Ageless]

Watching this with interest. In 36 years; never used foam when making a master

[WesGrimes]

Watching this with interest. In 36 years; never used foam when making a master

Just wait till I break out the Spackle for the fairing step!

This project's build techniques should not mistaken with anything remotely professional...

I was raised on a farm, so duct tape and bailing wire is all I have ever worked with.

[Ageless]

Spackle? You may want to check out a material; hydrocal. It's a very fine/hard setting plaster

We would set our headers and span with screen; then sweep in the 'plaster'

[WesGrimes]

Spackle? You may want to check out a material; hydrocal. It's a very fine/hard setting plaster

We would set our headers and span with screen; then sweep in the 'plaster'

Thanks for the lead. Looks like a better product for the job. I was quite sure you would think I was crazy for not using body filler. Just too much sanding and grinding involved for my taste...

Thanks,
Wes

[Ageless]

Once we began using NC machines; larger masters used a type of 'body filler', but smaller tools were still laid up with the old methods

[cappy208]

Hey Wes:

Been on vaca for two weeks, didn't check in across the 'pond'!

Looking good.

you are beginning to see a series of straight lines connecting the frames together. the centers of the foam patches actually need to be higher than the frames.

one topic to cover, is the use of 'battens'. a long flexible piece of wood is useful to 'float' along the length of the roof, so you can 'see' the whips and dips in the surface.

these whips and dips make for unsightly blemishes in the plug. then these are hugely magnified in the mold (and the finished product)

Use a batten to 'connect' the frames across the foam, to see how much you have to fill. it is a really artistic thing you are doing, and will take time to master the eye to get all the bumps out. you must have the battens long enough to connect four or more frames together, so the batten can take the shape of the shell.
another item of use is to get a piece of formica (or any cheap substitute) and make a super flexible sanding block out of it. make it about 1.5 times as long as your frame spacing is, so you can keep your hands above the wood frames, and let the 'softer' flexible part be gentle sanding the foam. if you dont you will begin to see hollows where the foam is, between the plywood frames. one issue with using a really long sanding block is to try to find long sandpaper. a long sanding belt, cut in half is quite nice. know anyone who has a 24" belt sander you could get an old belt from? you actually want to skim one end of the sandpaper off the luan on the center, and flex the other side down around the curve. you will begin to 'feel' the hump, and learn how to fair it acceptably.

the bottom of the notch you have would be nice to have a straight piece of wood in it to fair from the bottom up also. If you had a piece of wood in it it would be easier to foam too also. you could just remove the wood strip for the layup later. (just put some wax on the strip so the foam doesnt grab it)
If you have a piece of clear pine (no knots) and rip a couple pieces about 3/16" thick, they make excellent battens. You should only need about 6' or so of batten. you can experiment if you like thicker, or thinner. it depends on the radius you are working with. you must use clear wood because knots and defects in the wood effect the bending and flexing of the wood. you want battens that are free to conform to the shape of the object being faired out, not being influenced by other factors (damaged battens)[img]
you are beginning to see a series of straight lines connecting the frames together. the centers of the foam patches actually need to be higher than the frames.

john[/img]

[WesGrimes]

Hi John,

Thanks for all of the advice. I am learning as I go, so I need all the help I can get.

I intentionally shaved the foam below the wood rafters. The idea is that I will fiberglass over them with the dips and such, and then use filler to build everything up to round or flat or level as the case may be.

I am going to go get a piece of aluminum stock cut to the width of my roof (58") to use as a site gauge when fairing. It is hard to see in the picture, but there is 1/4" lip between the roof and the lip of that radius. It is to divert the water away from the side walls. This will make using some of the belt sander options challenging.



My biggest challenge at this point is finding enough money to buy more foam, fiberglass and resin. I blew all of my project money on the trailer frame.

[MrMatt]

I am enjoying reading about your build. Nice job, very interesting.

[cappy208]

Hey Wes:

Just read your earlier response.

You will notice that fairing to the roof, as you mentioned, will work. But, the visible rounded curve is what will be most noticable. The round curve of the teardrop is what will be the most striking part of your build. I have wracked my head on how to get this out of wood, and I can't seem to get any more ideas than you have.

However, fairing the curve front to back is going to make the most smooth appearance. Fairing across the roof will not let you clean up any whips from front to back. In my mind, the fairing of the roof is inconsequential. (Who is going to see the roof?)

But the side of the curve is what is going to be important to looks.

You shouldn't cover with glass yet. Any further fairing and filling you do will have a tendency to break off and/or chip off. The glass should cover the last of your filling, then sand the resin smooth for the final touch.
The earlier suggestion of the 'hydrocal' is a really good idea. but again, you don't want to put that onj over the glass. that should go on next.

I may have missed this earlier. What is the dimension of this wonder? L W H?

John

[Ageless]

You will need to sweep the radius. This would require a vertical indexing surface. Then you apply the hydrocal and using a radius 'sweep' and a steady hand; sweep the radius in. Any defects in either index surface will show in the radius.

[cappy208]

and to comment on ageless last:

the mention of installing a temporary batten in the lower 'wall to roof' groove would give you the vertical edge to fair to.

You mentioned that the roof itself is going to be lower than the top of the curve, then temporarily tack a strip of luan on the roof, to the height youwant the curve to come to, then you have the horizontle fairing edge to work from.

the outside of the curve is the toughy. I mentioned beltsanding paper, not an actual belt sander. a long flexible piece to affix the sandpaper to will let it flex over the radii, and you can (with practice) gain expertise in making this kind of curve.

using hydrocal, you can make a template of what you want the curve to look like, and following the top guide, and the bottom (not installed (yet)) guide rail, follow along, and 'screed' (like concrete) hydrocal in place to make the approximate curve..

Ill try to sketch up how it would work, but im not that good in paint!
How do i add a jpeg on here?

John[/url][/list]

[WesGrimes]

There is a great video on what I am doing.
http://www.youtube.com/user/fibreglast#p/u/12/-Ia4n1XoVpw

This is the approach that I was aiming for. I changed it up a bit by using Luan for some areas.

[cappy208]

that is an awesome training video. now if you go to the next video, you will see what specifically applies ot your case.

in advanced mold making 3 of 5 at minute 3:30 you see the guy using a form template to check the radii.

this is what you need to be doing. but you have no upper and lower edges to start from. you need to install an edge on top, and one on the bottom to fair to. using the roof like the guy did on the bottom of the form is going to be useless in your case. you need to form from the top of the curve, around the edge to the bottom of the curve.

The video is sort of misconstrueing the process, since they have an unlimited amount of cash, and time to get this project done. it has been quite a while since I have seen 5 gallon buckets of the foam mix. it was really expensive back then, and I am sure it has only gotten much worse.

It can be done quicker, and easier (especially in your case) since you aren't involving changing the profile. You are only changing the radii in one plane. The roof is easy, but the curves are the pain. the front panel will need fairing and smoothing too, since that will be visible.

[WesGrimes]

But I know something you don't know... I'm not left-handed!

I have taken off the side walls so that I could tape and foam everything cleanly. Check out this picture for what I am talking about:

Before I glass over it, I will cut the foam to allow me to re-attach the side walls, and then glass over the whole thing. This should give me the bottom edge that I believe you are referring to.

As for the drafting tool that was used in the video, I am planning to cut a template into a 2x6 and use that to check my radius. I threw something into Sketchup to illustrate:



Is this what you guys are referring to?

Thanks for the guidance. Keep it coming!
Wes

[cappy208]

that is exactly what i was trying to get across!!

the only thing is, that is depending on using the roof as a guide. the roof is independent of the curve. the 'visual' part is going to be the curve from front to back, in the area of the roof/wall joint. i would ignore the roof, and go from the top of the curve to the bottom where the wall is attaching. if your roof has dips or wiggles in it, that will show (and actually magnify) the dips. running off the top and side will blend them in so you don't see them. kind of like ignoring the area that is unseen, and concentrating on the side that will be so obvious.

Just had a further thought. looking at your plug, the shape you drew in sketchup is just what is needed, you should figure out how to use that using the plywood side rather than the roof as your guide, shown in the last photo, using it vertically, instead of horizontally. you just need to have an edge to work from that is un movable, that you can come back to time after time to check from.

the upper lip may be an uneven amount, 3/16 here, 3/8 there, as long as the side profile is constant it will look good. but working from the bottom up is key.

one other thought. how are you going to attach the side wall to the roof? if you mold in a say 1/4" lip, under the curve, about where the ply wood is, would be an ideal way to end one part, and leave a flat lip to bolt the side wall to. only one seam per side to show.

someone mentioned stiffness, and insulation. got some thoughts on stiffening, and wire runs.

using old xmas wrapping tubes cut in half. on your last layer of glass on the inside of the final layup, use these cardboard tubes to lay a layer or two of glass over. running longitudnally they will stiffen up the wall/roof wherever you put them AND give you a hollow to run wires into from front to back and sideways too. they can be cut out later if needed, or drilled into to attach stuff to, or using a snake you can hide wires in them.