MS MA-4SPA

[Cth6]

Was hoping someone has access to take some measurements for the accelerator pump on the 4SPA. I am going to make a 3D model that can be used as a plug to contain the proseal and facilitate making the filters much easier outside of the airplane. I have tried to find an engineering drawing but no luck.

Unfortunately I am away from my plane for a bit, otherwise I would measure mine. Anyone that wants the file to print, I am happy to share.

Chad

 

[Cth6]

I wanted to share progress on making filters outside of the airplane easier. This jig will allow you to invert the filter to let gravity help you and prevent any runs.

There are will be 4 pieces. Three empty curved pieces to hold the filter shape (2 on bottom and 1 the cut side). The 4th is the piece with the molded accelerator pump housing. In lieu of the 4th, I may just use the plug to make the piece. That would allow you to manipulate it to your setup.

I am going to make two filters after OSH. Will take photos and post results.

 

[PaulvS]

I wanted to share progress on making filters outside of the airplane easier. This jig will allow you to invert the filter to let gravity help you and prevent any runs.

There are will be 4 pieces. Three empty curved pieces to hold the filter shape (2 on bottom and 1 the cut side). The 4th is the piece with the molded accelerator pump housing. In lieu of the 4th, I may just use the plug to make the piece. That would allow you to manipulate it to your setup.

I am going to make two filters after OSH. Will take photos and post results.

View attachment 66519View attachment 66520View attachment 66521

It would help to have an oval cutout to hold the shape of the entire filter while it is curing. There also needs to be access to spread on or squirt in the sealant. Your molding parts will need to be made of a material or coated with something that will easily release from the cured sealant.

After I last modified a filter I thought that an improved process would be to first reinforce the pleated area around the cutout with sealant, before cutting it. That would make the filter less floppy and help to hold its shape while molding the indent.

 

[Cth6]

It would help to have an oval cutout to hold the shape of the entire filter while it is curing. There also needs to be access to spread on or squirt in the sealant. Your molding parts will need to be made of a material or coated with something that will easily release from the cured sealant.

After I last modified a filter I thought that an improved process would be to first reinforce the pleated area around the cutout with sealant, before cutting it. That would make the filter less floppy and help to hold its shape while molding the indent.

I was going to make a full filter cutout, but I surprised how those pieces hold the filter firm and in the correct shape. I will use a spray on release agent that I use when I do boat repairs. Epoxy, urethane and JB weld won’t stick to it. Cooking spray works wonders as well.

My current line of thinking is to work a blob into the mold as well as on the filter void. Any extra will squeeze out. The goal is to not over do it. This is not far off from the process you do on the plane.

 

[PaulvS]

I was going to make a full filter cutout, but I surprised how those pieces hold the filter firm and in the correct shape. I will use a spray on release agent that I use when I do boat repairs. Epoxy, urethane and JB weld won’t stick to it. Cooking spray works wonders as well.

My current line of thinking is to work a blob into the mold as well as on the filter void. Any extra will squeeze out. The goal is to not over do it. This is not far off from the process you do on the plane.

It will be interesting to hear about the end results and there certainly is an opportunity to improve the process!

I hope your side supports will hold the shape of the filter once it is cut. In my experience the filter lost a lot of its rigidity after the rubber ring was cut, because the pleated filter material doesn't have much strength on its own. Hence my thoughts about bridging that area with cured sealant before cutting the ring.

The Vans manual suggests to use auto wax as a release agent for the proseal but it wasn't very effective when I used it.