Discussion in 'Primus No:100' started by kaw550red, Dec 19, 2009.

  1. kaw550red

    kaw550red RIP

    Aug 22, 2004

    The Primus Trading Company was created by Optimus in 1962 and continued until 1976. It was used to sell the Primus brand stoves made by Optimus after they bought the brand name for liquid fuelled stoves from A B Bahco

    This post is written partly from memory so please excuse me if my memory is faulty. I no longer have the stoves to check some of the statements that I will make

    It may be a bit difficult to read as periodically you need to break off and read a link before continuing.


    As a collector I found 100s very collectable. As a user I found the concept confusing however they were made from at least 1911 up until 1962 by Hjorth & Bahco so must have been commercially viable. What bothers me is that effectively it was a 1.75 pint stove with the heat output of a 1/2 pint 96. Both models had 0.23 mm jets or rather the 0.23 mm prickers were used to clean the jets. The 100s did have some advantages over the 1/2 pint stoves. They needed refilling less often. They were more stable. The flame spread was much better than a 1/2 pint 96. The silent dampers were readily available to change the stove from a roarer to a silent stove. They were also available for Primus 96s but were more difficult to find.

    This is the "conventional" 100 using a vapourising tube. 1931 100

    However at least by 1961 Primus introduced another version of the 100 which used a conventional burner The burner plate on this one was made by Optimus in the late 1960s. 100/4043 There is also this one made in 1962 100/ 4043? Whilst the PTC model number is used the tanks were only marked 100 and I think that the 4138 is an assumption as pricker packets of that period only show a Primus 100/4043


    This stove is thought to be from from the earliest period of the the PTC because the model number on the box is that used by Optimus rather than 100/4043 used by Bahco.
    ]EARLY PTC 100/4128[/url] It is probably from 1962 or 1963

    Whilst this is the only very early PTC type of 100 that I have seen it is possible that this version also exists1931 100 as Optimus definitely got the fittings to produce this version


    The special rising tube is not obvious but if you look at the reserve lid you will see that it is the type that fit the original 100 tanks.

    The burner on this stove was marked as being made by Primus which is the marking used by Bahco up until 1962.

    You will also see that the Primus Trading Company is claiming to be the sole maker of Primus stoves even though they were made by Optimus and sold by the PTC

    1261236618-P100_ass_opt.jpg 1261236633-100_flame_opt.jpg 1261236645-100_lettering_opt.jpg 1261236659-P_100_pac_opt.jpg

    You will notice that the storage bag is yellow. I used yellow for silent stoves and orange for roarer stoves to try to reduce the possibility of me picking up the wrong parts for any tank

    MID 1960s PRIMUS 100s

    At some time in the 1960s Optimus ran out of 100 tanks and rebadged 45s and 48s as being Primus 100s. The tank was always marked as being 100. The stove only acquired the 4128 or 4138 suffix when the roarer or silent burner was fitted to the tank. This continued the policy when the original Primus 100s were sold in either a roarer or a silent form.

    The burner on the stove was marked Primus but it had 0763 marked on the hexagon section. I think that mark must have been made by Optimus and may mean that the stove was made in 1963. I do not know whether Bahco continued to date code their burners after the lettered codes stopped but I do have a late Bahco burner which is not date coded and that may mean that it was made between 1957 and 1962

    If the number is a date code and the stove was made in that year it means that by that time the PTC had issued a Bahco made 100 and a PTC 100 with the conventional 100 tank having a large connection in the top in a very short period of time

    1261251898-100_ass_opt.jpg 1261236909-100_Flame_opt.jpg 1261252050-100_pack_opt.jpg

    This is an unused PTC Primus 100/4128. 0984966 was very faintly printed on the box and I suspect that this was a code for 1966.

    The burner of this stove was marked PRIMUS SWEDEN and the top plate was also marked PRIMUS rather Than OPTIMUS PRIMUS so if the numbering on the box is a date code the Primus domestic stove parts lasted until 1966

    1261251607-Prim_100_4138_Ass.JPG 1261237595-Prim_100-4138_bo_opt_opt.jpg


    Any conventional Primus 100 made with original vapourising tubes will obviously have a 0.23 mm jet. Pricker packets show the Bahco Primus 100/4043 stoves as having a 0.23 mm nipple which halves the performance of the 2 pint burner. It seems to have been a pointless exercise changing from the conventional vapourising tube to a burner with the potential to double the heat output and then downgrading it to match the previous design

    The PTC period stoves that use the pre PTC burners should have the 0.32 mm nipple. Ian's stove definitely does have the bigger nipple


    The left burner was made in 1940. The centre burner was made in the 1950s. Whilst both have the same words on they are arranged in different ways. The right burner is a pre PTC Optimus burner. Either of the right burners is correct for the 100s made up until they ran out. If a stove is fitted with the earlier Primus burner it is probably a replacement burner. The unused stove suggests that they were still being used in 1966. The marking on the 1962-1969 burners was OPTIMUS SWEDEN written in a straight line. I think that the marking on burners made between 1969 and 1976 were marked simply SWEDEN or MADE IN SWEDEN you would have to check this marking. This gives you an idea of when the burner was made but not when it was fitted to a stove however it could not be originally fitted to a stove before the first date that the marking was used.


    There were conflicting policies within Optimus as to how to deal with the manufacture of multiple brand names. The tank makers were claiming that the tanks were made by the PTC. As far as I know there was no separate company for making the Primus brand stoves. They were all made by Optimus but only sold by the PTC.

    The parts makers seemed to acknowledge that Optimus were making both brands by marking the burners, silent outer caps and I think the flame rings OPTIMUS PRIMUS until 1969

    The PTC staff appeared to be trying to conceal that Optimus were making the Primus brand and simply marked the boxes PRIMUS TRADING COMPANY AB. This continued until the latter part of the 1960s when the boxes became marked “Manufactured by A B OPTIMUS” in smaller print than the PRIMUS TRADING COMPANY mentioned after the model number


    The bottom of the tank was marked MADE IN SWEDEN on all tanks made during the PTC period. This meant that one tank bottom was suitable for all makes.

    THE TEXT OF THIS TOPIC WAS REVISED ON 22/12/09. An incorrect paragraph had got into the text of one of the stoves. Sorry for the misleading information given to previous readers

    Regards Bryan
    Last edited by a moderator: Jul 2, 2015