Plastics repair with ABS cement: Difference between revisions

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*ABS Cement

::Use ABS plumbing cement with low VOCs (volatile organic compounds) . This is used as a sort of "bondo" to fill in cracks and deformations in the bodywork. Unlike bondo, the ABS cement will melt and fuse with the ABS bodywork, making a uniform repair material.

::Use ABS plumbing cement with low VOCs (volatile organic compounds) . This is used as a sort of "bondo" to fill in cracks and deformations in the bodywork. Unlike bondo, the ABS cement will melt and fuse with the ABS bodywork, making a uniform repair material. Home Depot or anywhere that sells plumbing supplies usually carries something like [http://www.amazon.com/Low-VOC-ABS-Cement-Black/dp/B000UG3GJQ Oatey Low VOC ABS Cement].

*Sandpaper and a sanding block

Line 28:

===Theory===

The theory behind the plastic repair is simple. A crack or a break in the ABS bodywork can be bonded back together by welding the plastic together. This can be done chemically, or by heat. Heat is used to make the primary bond, and then the surface imperfections are filled in with the ABS cement. This takes place in several steps.

The theory behind the plastic repair is simple. A crack or a break in the ABS bodywork can be bonded back together by welding the plastic together. This can be done chemically or by heat. Heat is used to make the primary bond, and then the surface imperfections are filled in with the ABS cement. This takes place in several steps.

The first figure shows the cross section of a break in the plastic. The top surface has a paint layer, and a relatively thick plastic layer.

The first figure shows the cross section of a break in the plastic. The top surface has a paint layer and a relatively thick plastic layer.

[[Image:theory01.gif]]

Start by sanding the paint off, to clear out the surface. This makes repainting REQUIRED. You can skip this step and only weld the break from the back. This makes a nice looking, but weaker, repair. If the paint gets into the ABS, it contaminates the bond, and you'll have to sand anyway.

Start by sanding the paint off, to clear out the surface. This makes repainting REQUIRED. You can skip this step and only weld the break from the back. This makes a nice-looking, but weaker, repair. If the paint gets into the ABS, it contaminates the bond, and you'll have to sand anyway.

[[Image:theory02.gif]]

A hot soldering iron melts together the two sides. Run the hot iron down the length of the fracture from the rear (unpainted side), with your finger on the painted side, moving gingerly up and down the surface. The idea is to keep the feeler fingertip from getting too hot. This is especially important if ~~one is~~ only welding one side. If your finger can't take the heat, neither can the paint. In this picture, both sides are welded.

A hot soldering iron melts together the two sides. Run the hot iron down the length of the fracture from the rear (unpainted side), with your finger on the painted side, moving gingerly up and down the surface. The idea is to keep the feeler fingertip from getting too hot. This is especially important if you are only welding one side. If your finger can't take the heat, neither can the paint. In this picture, both sides are welded.

[[Image:theory03.gif]]

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Next is a crack on the same piece.

The lower end of this piece shattered, and left a fracture running up it. The crack is a good candidate for repair.

The lower end of this piece shattered and left a fracture running up it. The crack is a good candidate for repair.

[[Image:inner_crack.01.jpg|170px]]

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[[Image:Leftside_top.01.jpg|170px]]

The lines show the fracture ran along the edge, which was reconstituted using ABS cement. As a result, the rounded edge of that corner is gone. It's now a sharp edge, which can easily go unnoticed. The ~~Orange~~ is also significant. That section was gone. Entirely gone. It was rebuilt by making a thin ABS layer, then rebuilding the surface. The rebuilt section was less than perfect, and cracked while back on the bike. This was because the shape it solidified into was not the same as the original shape. After welding the new crack to relieve the stress, it has been doing fine.

The lines show the fracture ran along the edge, which was reconstituted using ABS cement. As a result, the rounded edge of that corner is gone. It's now a sharp edge, which can easily go unnoticed. The orange is also significant. That section was gone. Entirely gone. It was rebuilt by making a thin ABS layer, then rebuilding the surface. The rebuilt section was less than perfect, and cracked while back on the bike. This was because the shape it solidified into was not the same as the original shape. After welding the new crack to relieve the stress, it has been doing fine.

[[Image:Leftside_top.02.jpg|170px]]

===Rebuilding plastic parts from molds.===

@@ Line 16: / Line 16: @@
 *ABS Cement
-::Use ABS plumbing cement with low VOCs (volatile organic compounds) . This is used as a sort of "bondo" to fill in cracks and deformations in the bodywork. Unlike bondo, the ABS cement will melt and fuse with the ABS bodywork, making a uniform repair material.
+::Use ABS plumbing cement with low VOCs (volatile organic compounds) . This is used as a sort of "bondo" to fill in cracks and deformations in the bodywork. Unlike bondo, the ABS cement will melt and fuse with the ABS bodywork, making a uniform repair material. Home Depot or anywhere that sells plumbing supplies usually carries something like [http://www.amazon.com/Low-VOC-ABS-Cement-Black/dp/B000UG3GJQ Oatey Low VOC ABS Cement].
 *Sandpaper and a sanding block
@@ Line 28: / Line 28: @@
 ===Theory===
-The theory behind the plastic repair is simple. A crack or a break in the ABS bodywork can be bonded back together by welding the plastic together. This can be done chemically, or by heat. Heat is used to make the primary bond, and then the surface imperfections are filled in with the ABS cement. This takes place in several steps.
+The theory behind the plastic repair is simple. A crack or a break in the ABS bodywork can be bonded back together by welding the plastic together. This can be done chemically or by heat. Heat is used to make the primary bond, and then the surface imperfections are filled in with the ABS cement. This takes place in several steps.
-The first figure shows the cross section of a break in the plastic. The top surface has a paint layer, and a relatively thick plastic layer.
+The first figure shows the cross section of a break in the plastic. The top surface has a paint layer and a relatively thick plastic layer.
 [[Image:theory01.gif]]
-Start by sanding the paint off, to clear out the surface. This makes repainting REQUIRED. You can skip this step and only weld the break from the back. This makes a nice looking, but weaker, repair. If the paint gets into the ABS, it contaminates the bond, and you'll have to sand anyway.
+Start by sanding the paint off, to clear out the surface. This makes repainting REQUIRED. You can skip this step and only weld the break from the back. This makes a nice-looking, but weaker, repair. If the paint gets into the ABS, it contaminates the bond, and you'll have to sand anyway.
 [[Image:theory02.gif]]
-A hot soldering iron melts together the two sides. Run the hot iron down the length of the fracture from the rear (unpainted side), with your finger on the painted side, moving gingerly up and down the surface. The idea is to keep the feeler fingertip from getting too hot. This is especially important if one is only welding one side. If your finger can't take the heat, neither can the paint. In this picture, both sides are welded.
+A hot soldering iron melts together the two sides. Run the hot iron down the length of the fracture from the rear (unpainted side), with your finger on the painted side, moving gingerly up and down the surface. The idea is to keep the feeler fingertip from getting too hot. This is especially important if you are only welding one side. If your finger can't take the heat, neither can the paint. In this picture, both sides are welded.
 [[Image:theory03.gif]]
@@ Line 70: / Line 70: @@
 Next is a crack on the same piece.
-The lower end of this piece shattered, and left a fracture running up it. The crack is a good candidate for repair.
+The lower end of this piece shattered and left a fracture running up it. The crack is a good candidate for repair.
 [[Image:inner_crack.01.jpg|170px]]
@@ Line 116: / Line 116: @@
 [[Image:Leftside_top.01.jpg|170px]]
-The lines show the fracture ran along the edge, which was reconstituted using ABS cement. As a result, the rounded edge of that corner is gone. It's now a sharp edge, which can easily go unnoticed. The Orange is also significant. That section was gone. Entirely gone. It was rebuilt by making a thin ABS layer, then rebuilding the surface. The rebuilt section was less than perfect, and cracked while back on the bike. This was because the shape it solidified into was not the same as the original shape. After welding the new crack to relieve the stress, it has been doing fine.
+The lines show the fracture ran along the edge, which was reconstituted using ABS cement. As a result, the rounded edge of that corner is gone. It's now a sharp edge, which can easily go unnoticed. The orange is also significant. That section was gone. Entirely gone. It was rebuilt by making a thin ABS layer, then rebuilding the surface. The rebuilt section was less than perfect, and cracked while back on the bike. This was because the shape it solidified into was not the same as the original shape. After welding the new crack to relieve the stress, it has been doing fine.
 [[Image:Leftside_top.02.jpg|170px]]
 ===Rebuilding plastic parts from molds.===