With all the tubes I knew I'd better get started on the tube seams.
I started with my new method of laying the filler into the seam using a dull hobby knife blade. This will keep the filler only in the seam where you want it to be.
The blade is dipped into the filler and the back side of the blade is wiped off on the lip of the filler jar. I leave the filler on only one side of the blade for a cleaner transfer into the seam.
Set the blade and filler drop in the seam. Drag the blade down the seam trough. Go back and forth leaving an even line of filler.
In filling the seams this way you will be able to do about and inch and a half before going back for more filler.
Here's the BT-101 tube with filler applied in the seams before sanding. Right now the filler is in the seam and slightly bulging over the top. Picture the filler in the shape of a mushroom.
Here's the BT-101 tube with filler applied in the seams before sanding. Right now the filler is in the seam and slightly bulging over the top. Picture the filler in the shape of a mushroom.
Let the filler dry thoroughly overnight before sanding.
Time spent on build: 1:00 seam filling
Total time on build so far: 6:15
What kind of filler are you using?
ReplyDeleteThat's thinned Elmer's Carpenter's Wood Filler.
ReplyDeleteGo here:
http://www.howtobuildmodelrockets.20m.com/TheBestToolsPage2.html
and scroll down to the Elmer's Wood Filler section for the mix ratios and tips.
This stuff works to fill "most" of the body tube seams.
The remainder is filled using primer. Spray on the primer and sand off.
Thanks,
Chris
When sanding, do you sand "with the grain" (along the length of the spiral) or "across the spiral" meaning 90 degrees? Or does it matter? How fine of sandpaper are you using?
ReplyDeleteHi Kirk,
DeleteI sand across the "grain" of the spiral. If you sand with the grain or direction of the spiral you might knock the filler out of the seam.
I start with 220 grit (my 220 is pretty fine, you might want to go with 320) to remove the bulk of the filler bead. You might scratch the tube a little, try to keep that to a minimum. Then smooth with 400. Follow with a coat of spray filler/primer and sand with 400 to remove the fuzzies.
Can you elaborate as to why the need to fill the seams on the tubes when they will be under the plastic wraps? The directions talk a bit about filling seams in the opening pages but don't say where and when this is needed. I assumed they meant the seams in the wraps.
ReplyDeleteHi Unknown,
DeleteYou don't have to. I thought it would be faster than marking and working around all the wrap locations. I would think Estes is referring to filling the body tube seams. You can also fill the joint edges in the wraps. Interesting point, on the new #1969 Saturn V kit you only have to fill the seams on the larger lower tube and short CM tube. The other tube is covered by a wrap.
Thanks for the info. As I get farther into the build I realize how vague the directions have been. It seems that the wraps only cover parts of the main body tube and not the whole thing? For a $95 kit, I think there are about $3 worth of materials in this box.
ReplyDeleteHi Michael,
DeleteWhen I bought my first model rocket in 1969, I remember my Mother saying: "There's probably only 20 cents worth of materials here!" On the Saturn V kit, the vacuform wraps supply the detail, between them is the smooth round body like on the real Saturn V. They had to keep it light.
So now seeing the need to fill the seams, I set out for the Elmer's carpenter's wood filler. Now I finally have it but it looks nothing like the mix you used in this thread. The link in an earlier post for mix ratios is no longer valid. What did you thin it with?
DeleteHi Michael,
DeleteYou have to thin the filler with water. Here's a link that should work with all the information: http://modelrocketbuilding.blogspot.com/2010/09/carpenters-wood-filler-mix-ratios.html
I really do appreciate all your advice, now you're going to shake your head and laugh at me. I was finding these seams too small to try to fill so I came up with the brilliant idea do paint the whole lower tube in several layers of filler primer. It didn't fill the seams but did make them less noticeable. What I didn't bargain for is now the wraps won't stick to the primer with the spray adhesive. Any suggestions? Initial attempts so sand the wrap areas are not looking promising. I may have to go to the craft store and buy new cardboard tubes.
DeleteHi Michael,
DeleteI don't know what type of filler/primer you used. Did you sand almost all of the filler/primer off leaving it in the seams? Lightly with 220 grit, then 400 to smooth it out.
I also don't know what type of spray adhesive you used. The "77" type should hold it in place, whether you used primer or not. The ends of the wraps usually have to have a little CA glue to close them up.
You won't find the correct diameter BT-101 tubes at a regular craft store. Those would be available at Balsa machining Service (BMS) or erockets.biz.