Martin Mars XPB2M-1R Scratchbuild - 1943-123 inch Wingspan

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Neons
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Re: Martin Mars XPB2M-1R Scratchbuild - 1943

Post by Neons »

Start of Epoxy Coating the Mars
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Did the bottom of the hull today with 2 - 3oz, pieces of cloth with epoxy. The Epoxy I used is Home Depot - Parks- Super Glaze. Works well but has a slow cure. If sunny tommorow I will do the sides with 0.75 oz. cloth. I will air dry outdoors with the sun beating on it. My garage is cool and high humidity which retards drying. That will slow the job down some.

I found a company with 2 quarts for about the same price $23 and the shipping is $16 to my area. 1 gallon is $39.50 Same shipping if under 10 lbs. Which it should be. Remember this is a hard table glazing epoxy and it works fine for my models. I read some good reports on a forum on this brand. Read instructions carefully. 9 times out of 10 it is a bad mix that gives problems. Mix by weight or equal measuring cups like those plastic pill things used in hospitals for a precise measure. Mix a good 5 minutes thoroughly. If you do not trust it, go with West System and pay double.
http://www.shopmaninc.com/kk121.html

I use a postage scale to get equal parts. I usually mix up a couple ounces at a time in a 3 oz. plastic cup. Set the scale to zero with the cup. Pour in Part A - 1 oz. then add the other Part B - 1 oz. part to read 2 oz.. Then I mix it up.

How about it readers. You are allowed to ask questions and leave comments throughout the Forum.
Attachments
Layed up the 2 layers and setting.
Layed up the 2 layers and setting.
Cut 2 layers of 3oz. cloth.
Cut 2 layers of 3oz. cloth.
Bob Pacheco
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Re: Martin Mars XPB2M-1R Scratchbuild - 1943

Post by tomapowa »

Wow Bob!.... heaps and heaps of progress I see! :D
Can't wait to hopefully see her fly this summer... simply an amazing build!
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Re: Martin Mars XPB2M-1R Scratchbuild - 1943

Post by Neons »

Wing Epoxy - Fuselage Primer Paint
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Hi Tom Thanks. Here is more.
I got to finish the mid wing and nacelles today with epoxy and cloth skin.. The fuselage got primed. It has to be spackled lightly in a few places. It is pretty smooth though. I may do the wing tomorrow.

I bought some flat Americana Blue at Home Depot yesterday. It is their Behr brand. I like Walmart craft paint for lightness though. The Behr has color chips so I can nearly get the paint mixed right on to the shade I want. I bought the 8oz. samplers they have on the counter just under $4. It is a good size. The paint is flat and is listed as a finish paint with built in primer. It sprayed very well after I thinned it down over 50% with windshield cleaner for my airbrush. The window washer has alcohol in it to prevent freezing in a car and makes a good thinner.

The epoxy blended the Depron foam very well. you would have a hard time figuring what is wood and what is foam. So much for the purist balsa builders. Their moaning will have no basis here for this type of aircraft.
Attachments
This should easily take panel lines also when ready.
This should easily take panel lines also when ready.
A couple of coats and ready to finih with spckling in some areas
A couple of coats and ready to finih with spckling in some areas
This is the hatch cover. It is the finish and primer in one paint. It layed beautiful with airbrush. I use folded old newspaper between coats to rub it.
This is the hatch cover. It is the finish and primer in one paint. It layed beautiful with airbrush. I use folded old newspaper between coats to rub it.
The wing is very smooth. . The floats are started to be glassed.
The wing is very smooth. . The floats are started to be glassed.
Bob Pacheco
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Re: Martin Mars XPB2M-1R Scratchbuild - 1943

Post by Neons »

Continue to do sanding and priming today. I have the fuselage ready for final coat and the wing is just primed and light spackle. It is coming out real nice. The ing floats are sanded and ready to paint also.

I believe I will have 2 seperate orders coming in tomorrow. More epoxy and my light weight 0.7oz. cloth. I can do the rest of the wings and tail soon.
Attachments
4-24-12 Sanding and Primer (4).jpg
Bob Pacheco
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Re: Martin Mars XPB2M-1R Scratchbuild - 1943

Post by Neons »

Nacelle Air Intakes
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Got my air intake and air outlet to help cool the electronics functional.They should all work very well. The plastic food storage cowlings are starting to look better now. All my new glass cloth and epoxy came in so I can finish up the glass coating now.
Attachments
Air Flow Though the scoops.
Air Flow Though the scoops.
4-27-12 Nacelle Air Intakes (4).jpg
Fitted and primed. Air for motor vent cooling is wood veneer, 1/64" plywood would be better.
Fitted and primed. Air for motor vent cooling is wood veneer, 1/64" plywood would be better.
The oil cooler scoop underneath is dremel routed to a channel with a 1/4" stone. Balsa wood. After drilling an air outlet hole under it, glue in place.
The oil cooler scoop underneath is dremel routed to a channel with a 1/4" stone. Balsa wood. After drilling an air outlet hole under it, glue in place.
Test fit. It is so much easier to shape while on the pine stick. 15 minutes each.
Test fit. It is so much easier to shape while on the pine stick. 15 minutes each.
Pine. 3/4"X1/2" Rough cut tapers part way. Drill pilot hole. Route out with a Dremel tool tapered stone. Cut off and sand.
Pine. 3/4"X1/2" Rough cut tapers part way. Drill pilot hole. Route out with a Dremel tool tapered stone. Cut off and sand.
Bob Pacheco
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Re: Martin Mars XPB2M-1R Scratchbuild - 1943

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I got all 4 motors worked on and fitted. I had to remove all the threaded shafts and replace with solid straight shafts with some ground in modifications. it took over 4 hours for mods. They all are now collet prop adapters.

I have the bottom of the outer wings to epoxy now. The rudders and elevator has epoxy outside the rudders and the top of the elevator. The inside rudders and elevator bottoms will be polyurethane and glass cloth. They are less prone to damages. This will help keep the tail weight down some also.

The next sunny day I am going to put the finish blue on some parts. Saturday maybe.
Bob Pacheco
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Re: Martin Mars XPB2M-1R Scratchbuild - 1943

Post by Blip »

Looks like I'm due to come by again, always better in person......Don.
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Re: Martin Mars XPB2M-1R Scratchbuild - 1943

Post by chistech »

Beautiful work Bob. Another beauty. This might look great at the static show too. Give people an idea of what goes into a scale aircraft.

Ted
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Re: Martin Mars XPB2M-1R Scratchbuild - 1943

Post by Neons »

Ted,
Thank you sir. I will bring this and Emily if they fit in my truck. I am planning just homebuilt foanies. I do not know how much of the finish paint will be done yet. I still have panel lines and decals to figure out. Very time consuming here with all the sanding and painting still going on right now.
Bob Pacheco
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Re: Martin Mars XPB2M-1R Scratchbuild - 1943

Post by Neons »

Base Finish Coats On
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Spent the day mostly spraying and sanding the off white color. The original colors had a white bottom. I have to do a little more touch up tomorrow on the white. I am trying to locate some graphic ink pens that will not skip on the paint when I draw the panel lines. There is an ingrediant that makes it skip in the paint. I had those problems on my other plane last year.

Hi Don, I just saw your reply. Actually you or anyone in the club are always welcome to come by here if you are down this way. Maybe I can help someone with build info or just BS a storm. It should be about readyy to view at the airport next week, Still got electronics to finish also.
Attachments
The white in the rear needs a softened edge. This is to sharp. Panel lines next
The white in the rear needs a softened edge. This is to sharp. Panel lines next
Hull bottom coated
Hull bottom coated
Bottom has 2 coats of off white and 1 more coat. The photo color is not quite right. It is white.
Bottom has 2 coats of off white and 1 more coat. The photo color is not quite right. It is white.
Blue all sanded and finished blue. Ready for panel lines now.
Blue all sanded and finished blue. Ready for panel lines now.
Bob Pacheco
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