Cover plugs TP10 black

Cover plugs in the TP10 series are ribbed end plugs in polyethylene (PE) for square structural tube. The plug is pressed into the open end of the tube and closes it completely; that protects against dirt and moisture, hides sharp cut edges and gives the structure a finished end.

Polyethylene suits this type of part better than most other materials. The plastic is tough and springy, so the plug takes up variations in dimension without cracking, and it absorbs practically no water. PE also takes most cleaning agents; a plug sitting in a frame that is hosed down every evening looks the same after several years. The density is below 1 g/cm³, so not even a full box weighs very much.

The ribs are the point of the series. The shank has ribs running around it that deform just enough when the plug is pressed in, which gives clamping force against the inside of the tube across a wide range of wall thicknesses. Each size is made for a range of wall thicknesses, for the smallest tubes 1.0 to 2.0 mm, and you therefore do not need to know exactly what wall thickness your tube has as long as the outer dimension matches; for some sizes there are also separate versions for heavier material.

The sizes cover square tube from 10x10 all the way up to 200x200 mm, in 31 dimensions. On the smallest plugs the total height lies between 14 and 16 mm, of which the visible collar stands about 4 mm outside the tube end; exact dimensions for each size are in the data sheet. The surface is matte and the color black, which blends in against powder coated frames and black profile systems. All sizes share the same design, so a build with mixed tube dimensions can be plugged uniformly.

The uses in a Swedish workshop are many: welded machine frames, guard railings, transport carts, shop fittings, furniture legs and test rigs. In short, everywhere a cut square tube leaves an open end. At the same time the plug stops chips, dust and wash water from collecting inside the tube, which is otherwise a classic source of corrosion from the inside on steel tube.

The working environment is a reason that is often forgotten. A cut tube end has burrs and sharp corners, and a plug in PE is the cheapest way to make the frame safe to grip. The difference shows straight away for the person pulling a cart shift after shift. A frame without plugs also feels unfinished, however well it is welded.

Black is also the right color outdoors. The carbon black pigment gives polyethylene good protection against UV light, so the plugs work on railings and gates that stand outside all year round as well.

Fitting calls for no tools. Press the plug in by hand or tap it into place with a rubber mallet, and then it stays there by the clamping force of the ribs. If the tube is to be rewelded the plug can be pried loose with a flat screwdriver and used again. No glue is needed and none should be used; the clamping force is the whole design.

Choose the size by the outer dimension of the tube, not the inner one. Measure with a caliper if you are unsure; a plug that is one step too small falls out, and one that is too large does not go all the way in. Also check that the wall thickness lies within the stated range of the version, since outside it the grip gets worse.

The pack quantity follows the size of the plug; the smallest sizes are supplied in 1000 pieces. That volume suits series production and running manufacture rather than one off projects. For you who build frames in volume it means a plug that is always in the box when the line is running.

Not sure which size suits your tube? Get in touch with us.