Now that the last blitz of rental repairs, and fall chores is over, I can slow down and show you the latest restoration project, restoration work on a vintage 1950's Frigidaire range, model RS-35 that I picked up on the used market here. The missing knob, with its incised lettering... I searched for a few months and gave up, deciding it was better to try to reproduce it, though I've never done any casting or molding work previously. This is my 4th or 5th try to get the knob poured correctly, and I'm finally happy enough with the result to use it.
The fun part of this has been learning how to make a rubber mold using a two part product that you mix up and pour over the knob, then working with a two part resin to make the new knob itself.
Here's the range (after a huge clean up job and some polishing), with the missing knob and not all the knobs yet have the black in the lettering... that is still in progress, and this will include the oven knobs up top as well. Since I can't figure out how to insert photos here, I'll try to attach them at the end.
This Frigidaire range knob is no longer available, and the control is quite unusual, as you will notice that it goes from High to Simmer on one side, not like modern knobs, and the electric burner control itself has been made to do this... presumably as back then in the era of canning, they thought many times you would bring the pot to a boil and then turn it straight down to simmer, during your food production. My new knob on left side, is almost but not quite identical to the original style.
I'm sure I've made about all the mistakes a person can make, and now at last have reproduced this little guy shown above. I have yet to make a second mold for creating a spare "FRONT" burner knob, but the new "REAR" burner knob shown, has at last come out with a minimum of defects and bubbles, and with the orientation of the shaft receptacle on the back in the correct direction, the shaft entering at the correct angle, and the edges of proper thickness. All these aspects have been a bit of a challenge. Even after all this work, I've had to take my newly poured knob out to the little range in my shop, and work with a fine file in the shaft hole to make it fit exactly... it was a hair too tight to slide down onto the control shaft.
I would have used the original electrical controls to make the hole in the back of the knob, but they are very difficult to access or remove on this old range, and they currently are working, so I'm reluctant to even mess with them. Instead I made a reproduction wooden shaft piece to use when molding. The metal washer epoxied round the shaft is so that the knob back will clear the two screws that stick out of the face of the range, and that hold the burner control in place. The wood part must be liberally and thoroughly greased with vaseline, or it will never come out of that resin. Here's the mold and the shaft insert for the back. Also, you do not want to use any kind of mold release agent on the rubber mold, as that will cause odd pockets to be put into the resin, and when you go to add color for filling in the lettering, you'll see this host of little black pockets. The rubber mold releases easily from the resin, without any kind of greasing or mold release. I discovered that you can't just use your good old kitchen counter for this job, as it isn't quite level, and the knob when poured must come out exactly level or the edges of the knob will be too thin on one side.
The little metal insert in the top of the knob... I was not able to find a proper stainless one, but at the hardware store there were these little flat cover caps which turned out to be ok... I used the 5/8" size. The goal was to dome the top of them as you buy them with a flat top. I got out the old washer can in the shop, (what the heck are these domed washers used for? You can find them still at the hardware store...) I suspect the washer I used underneath might have been from the end of a shock absorber? The conventional carriage bolt has a head that just fit into the cap, and I could give the bolt a couple quick raps with the hammer to press a dome down into the cap. Then I could grease it with vaseline and set it into the bottom of the mold with its little feet sticking upward before pouring the resin in. Here's the parts... a flat cover cap at the top, and the finished domed one at bottom left.
Here's the method, and it is worth buying a few extra caps as its difficult to get them perfectly centered on the curved surface when you're pounding:
So that is my latest adventure. Today I hope to slow down enough to cast a second rubber mold for the "FRONT" knob. Casting rubber was found at the Michaels craft supply store, under the name Alumilite Amazing Mold Maker, and the resin for casting also available at Michaels, called Amazing Casting Resin (selected out of many other casting resins because it cures a nice white color). It took 10 ml of the A part casting resin, and 10 ml of the B part to exactly fill this mold and the little measuring cups are right there with the resin kit. The mold was made by watching U-tube video of a sweet tempered Etsy crafter who gave you the secrets with a smile, found here:
My mold container was an overturned small plastic yogurt container with the bottom cut off it and that was sealed down onto a piece of clear contact paper before I poured the two part rubber mold. My knob won't last as well as the original Bakelite knob, but its way better than forcing a mismatched modern knob onto the shaft and guessing at where the heat temperatures are. Modern Frigidaire knobs don't have the same shape of shaft... nor do any other makes seem to use this shaft with the little raised spline.... this little guy is definitely a thing of the past. Hope this encourages some of you who have to deal with this sort of restoration to get your beloved stove back up.
I should mention that the original knob is not as strong, as it has a hollowed out back side with an internal "tube" that fits around the shaft, and the ends of that tube break apart and give way over the years. If you have this range, I highly recommend that you get some epoxy putty and work it in down around that shaft tube to reinforce it before you've lost that original knob to cracking. If you lost a small part of the shaft tube already, you can reform it when you put in that epoxy putty. Since the new one I poured has a fully filled back, I suspect that part will be stronger than the original, but only time will tell. I doubt the casting resin is as strong as the original Bakelite.
Roberta
The fun part of this has been learning how to make a rubber mold using a two part product that you mix up and pour over the knob, then working with a two part resin to make the new knob itself.
Here's the range (after a huge clean up job and some polishing), with the missing knob and not all the knobs yet have the black in the lettering... that is still in progress, and this will include the oven knobs up top as well. Since I can't figure out how to insert photos here, I'll try to attach them at the end.
This Frigidaire range knob is no longer available, and the control is quite unusual, as you will notice that it goes from High to Simmer on one side, not like modern knobs, and the electric burner control itself has been made to do this... presumably as back then in the era of canning, they thought many times you would bring the pot to a boil and then turn it straight down to simmer, during your food production. My new knob on left side, is almost but not quite identical to the original style.
I'm sure I've made about all the mistakes a person can make, and now at last have reproduced this little guy shown above. I have yet to make a second mold for creating a spare "FRONT" burner knob, but the new "REAR" burner knob shown, has at last come out with a minimum of defects and bubbles, and with the orientation of the shaft receptacle on the back in the correct direction, the shaft entering at the correct angle, and the edges of proper thickness. All these aspects have been a bit of a challenge. Even after all this work, I've had to take my newly poured knob out to the little range in my shop, and work with a fine file in the shaft hole to make it fit exactly... it was a hair too tight to slide down onto the control shaft.
I would have used the original electrical controls to make the hole in the back of the knob, but they are very difficult to access or remove on this old range, and they currently are working, so I'm reluctant to even mess with them. Instead I made a reproduction wooden shaft piece to use when molding. The metal washer epoxied round the shaft is so that the knob back will clear the two screws that stick out of the face of the range, and that hold the burner control in place. The wood part must be liberally and thoroughly greased with vaseline, or it will never come out of that resin. Here's the mold and the shaft insert for the back. Also, you do not want to use any kind of mold release agent on the rubber mold, as that will cause odd pockets to be put into the resin, and when you go to add color for filling in the lettering, you'll see this host of little black pockets. The rubber mold releases easily from the resin, without any kind of greasing or mold release. I discovered that you can't just use your good old kitchen counter for this job, as it isn't quite level, and the knob when poured must come out exactly level or the edges of the knob will be too thin on one side.
The little metal insert in the top of the knob... I was not able to find a proper stainless one, but at the hardware store there were these little flat cover caps which turned out to be ok... I used the 5/8" size. The goal was to dome the top of them as you buy them with a flat top. I got out the old washer can in the shop, (what the heck are these domed washers used for? You can find them still at the hardware store...) I suspect the washer I used underneath might have been from the end of a shock absorber? The conventional carriage bolt has a head that just fit into the cap, and I could give the bolt a couple quick raps with the hammer to press a dome down into the cap. Then I could grease it with vaseline and set it into the bottom of the mold with its little feet sticking upward before pouring the resin in. Here's the parts... a flat cover cap at the top, and the finished domed one at bottom left.
Here's the method, and it is worth buying a few extra caps as its difficult to get them perfectly centered on the curved surface when you're pounding:
So that is my latest adventure. Today I hope to slow down enough to cast a second rubber mold for the "FRONT" knob. Casting rubber was found at the Michaels craft supply store, under the name Alumilite Amazing Mold Maker, and the resin for casting also available at Michaels, called Amazing Casting Resin (selected out of many other casting resins because it cures a nice white color). It took 10 ml of the A part casting resin, and 10 ml of the B part to exactly fill this mold and the little measuring cups are right there with the resin kit. The mold was made by watching U-tube video of a sweet tempered Etsy crafter who gave you the secrets with a smile, found here:
My mold container was an overturned small plastic yogurt container with the bottom cut off it and that was sealed down onto a piece of clear contact paper before I poured the two part rubber mold. My knob won't last as well as the original Bakelite knob, but its way better than forcing a mismatched modern knob onto the shaft and guessing at where the heat temperatures are. Modern Frigidaire knobs don't have the same shape of shaft... nor do any other makes seem to use this shaft with the little raised spline.... this little guy is definitely a thing of the past. Hope this encourages some of you who have to deal with this sort of restoration to get your beloved stove back up.
I should mention that the original knob is not as strong, as it has a hollowed out back side with an internal "tube" that fits around the shaft, and the ends of that tube break apart and give way over the years. If you have this range, I highly recommend that you get some epoxy putty and work it in down around that shaft tube to reinforce it before you've lost that original knob to cracking. If you lost a small part of the shaft tube already, you can reform it when you put in that epoxy putty. Since the new one I poured has a fully filled back, I suspect that part will be stronger than the original, but only time will tell. I doubt the casting resin is as strong as the original Bakelite.
Roberta
